DOCSLIB.ORG

Structural and Kinetic Analysis of Escherichia Coli Signal Peptide Peptidase A

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Structural and Kinetic Analysis of Escherichia Coli Signal Peptide Peptidase A Structural and Kinetic Analysis of Escherichia coli Signal Peptide Peptidase A by Apollos C. Kim B.A. (Psychology), Simon Fraser University, 2001 B.Sc. (Biology), Seoul National University, Korea, 1992 Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy in the Department of Molecular Biology and Biochemistry Faculty of Science Apollos C. Kim 2013 SIMON FRASER UNIVERSITY Summer 2013 All rights reserved. However, in accordance with the Copyright Act of Canada, this work may be reproduced, without authorization, under the conditions for “Fair Dealing.” Therefore, limited reproduction of this work for the purposes of private study, research, criticism, review and news reporting is likely to be in accordance with the law, particularly if cited appropriately. Approval Name: Apollos C. Kim Degree: Doctor of Philosophy (Molecular Biology and Biochemistry) Title of Thesis: Structural and kinetic analysis of Escherichia coli signal peptide peptidase A Examining Committee: Chair: Frederic Pio, Associate Professor Mark Paetzel Senior Supervisor Associate Professor Nicholas Harden Supervisor Professor Edgar C. Young Supervisor Associate Professor Dipankar Sen Internal Examiner Professor Ross MacGillivray External Examiner Professor Department of Biochemistry and Molecular Biology University of British Columbia Date Defended/Approved: June 19, 2013 ii Partial Copyright Licence iii Abstract Secretory proteins contain a signal peptide at their N-terminus. The signal peptide functions to guide proteins to the membrane and is cleaved off by signal peptidase. The remnant signal peptides must be removed from the membrane to prevent their accumulation which can lead to membrane destabilization. Escherichia coli signal peptide peptidase A (SppAEC) has been identified as a major enzyme that processes the remnant signal peptide to smaller fragments. SppAEC, however, had remained uncharacterized such that the structure, catalytic mechanism, and substrate preference were unknown. I have cloned, overexpressed, purified and crystallized an active soluble domain of SppAEC. We have determined the structure of SppAEC by X-ray crystallography, which revealed that: 1) SppAEC has two similar alpha-beta domains (despite limited sequence identity), 2) SppAEC forms a tetramer that results in a dome shaped structure with a hydrophobic interior and hydrophilic exterior, 3) the four active sites within the cavity each utilize a Ser-Lys dyad where the general base (Lys209) arrives from the N-terminal domain and the nucleophile (Ser409) from the C-terminal domain. I have further characterized SppAEC using steady-state kinetics and cocrystallization. Using a series of fluorometric peptide substrates, I discovered that leucine is the most preferred residue at the P1 substrate position. I cocrystallized an SppAEC active site mutant (K209A), in complex with the substrate Z-LLL-MCA. The electron density within the active site of the 1.95 Å resolution structure is consistent with the carbonyl carbon of the substrate’s C-terminal leucine being covalently linked via an ester bond to the Ser409 O, thus revealing an acyl-enzyme complex in SppAEC. This is direct evidence that Ser409 O serves as a nucleophile in the SppAEC catalyzed reaction and confirms the identity of the S1 and S3 substrate specificity pockets. Lastly, I measured the pH dependence of both WT and S431A enzymes (Ser431 Ois hydrogen-bonded to Lys209 Nζ). The pH-rate profiles are consistent with S431 playing a role in lowering the pKa of the lysine general base, which would be critical for activity at iv physiological pH. We propose that the active site architecture of SppAEC may be best described as a Ser-Lys-Ser triad. Keywords: Protein translocation; signal peptide processing; signal peptide peptidase; Ser-Lys-Ser triad catalysis; steady-state kinetics; X-ray crystallography. v Dedication To God who is the reason for my life vi Acknowledgements First of all, I thank my senior supervisor, Dr. Mark Paetzel, who provides the best environment and guidance for doing and learning science. He has taught me how to enjoy science not just as a job but as a calling. Also, my two other supervisory members, Dr. Nicholas Harden, who has first hired me as a teaching lab technician, has trained me, and has been my “big brother”, and Dr. Edgar Young, who knows how to spread the passion for science and is always willing to help. It has been such a blessing that I could work under this wonderful group of mentors. I thank Dr. Ross MacGillivray for taking time to be my external examiner at the last- minute request. I thank Dr. Dipankar Sen for evaluating my work as an internal examiner and Dr. Frederic Pio for chairing my dissertation defense. I thank my current and former lab-mates, Deidre de Jong-Wong, Chuanyun Luo, Jae- Yong Lee, Ivy Chung, Kelly Kim, Charles Stevens, Sung-Eun Nam, Daniel Chiang, Suraaj Aulakh, Linda Zhang, Minfei Fu, Michael Ungerer and Zohreh Sharafianardekani. I am indebted to Deidre, Chuanyun, and Jae-Yong who have been my friends. Sung- Eun and Daniel have been excellent shareholders in this S49 peptidase family project. I thank Dr. Bruce Brandhorst and Dr. Lynne Quarmby who were wonderful bosses. I also thank Jenny Lum, Duncan Napier, Christine Beauchamp, Nancy Suda, Mimi Fourie, and Livleen Diwana who have been great to work with. Finally, I know I could not finish this without my family who have always supported me and have believed in me. Thank you all. vii Table of Contents Approval .......................................................................................................................... ii Partial Copyright Licence ............................................................................................... iii Abstract .......................................................................................................................... iv Dedication ...................................................................................................................... vi Acknowledgements ....................................................................................................... vii Table of Contents .......................................................................................................... viii List of Tables .................................................................................................................. xi List of Figures................................................................................................................ xii Glossary ........................................................................................................................xiv 1. Signal peptide peptidase A .................................................................................. 1 1.1. The function of signal peptides in protein translocation ........................................... 1 1.2. The structure of signal peptides .............................................................................. 5 1.3. Discovery of E. coli signal peptide peptidase A ....................................................... 8 1.4. S49 family proteases ............................................................................................ 10 1.5. Catalytic mechanism of serine proteases ............................................................. 11 1.5.1. Principles of catalysis ................................................................................ 16 1.5.2. pH dependence ......................................................................................... 17 1.5.3. Temperature dependence ......................................................................... 19 1.6. Substrate specificity .............................................................................................. 22 1.7. Aims of this thesis ................................................................................................ 24 2. Crystallographic analysis of E. coli signal peptide peptidase A with an empty active site ................................................................................................ 26 2.1. Introduction .......................................................................................................... 27 2.2. Methods and materials ......................................................................................... 27 2.2.1. Cloning...................................................................................................... 27 2.2.2. Overexpression and purification of SppAEC proteins .................................. 28 2.2.3. Crystallization and data collection ............................................................. 30 2.2.4. Structure determination and analysis ........................................................ 32 2.2.5. Figure preparation and Protein Data Bank accession codes ..................... 34 2.3. Results and discussion ......................................................................................... 34 2.3.1. Protein expression and purification ........................................................... 35 2.3.2. The protein fold of SppAEC ........................................................................ 35 2.3.3. The shape, dimensions, and surface features of the SppAEC tetramer .................................................................................................... 37 2.3.4. The assembly of Ser-Lys dyad active sites from adjacent domains and monomers .........................................................................................
Load more

Recommended publications
  • The Secretory Proprotein Convertase Neural Apoptosis-Regulated Convertase 1 (NARC-1): Liver Regeneration and Neuronal Differentiation
    The secretory proprotein convertase neural apoptosis-regulated convertase 1 (NARC-1): Liver regeneration and neuronal differentiation Nabil G. Seidah*†, Suzanne Benjannet*, Louise Wickham*, Jadwiga Marcinkiewicz*, Ste´phanie Be´langer Jasmin‡, Stefano Stifani‡, Ajoy Basak§, Annik Prat*, and Michel Chre´ tien§ *Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, 110 Pine Avenue West, Montreal, QC, H2W 1R7 Canada; ‡Montreal Neurological Institute, McGill University, Montreal, QC, H3A 2B4 Canada; and §Regional Protein Chemistry Center and Diseases of Aging Unit, Ottawa Health Research Institute, Ottawa Hospital, Civic Campus, 725 Parkdale Avenue, Ottawa, ON, K1Y 4E9 Canada Edited by Donald F. Steiner, University of Chicago, Chicago, IL, and approved December 5, 2002 (received for review September 10, 2002) Seven secretory mammalian kexin-like subtilases have been iden- LP251 (Eli Lilly, patent no. WO 02͞14358 A2) recently cloned tified that cleave a variety of precursor proteins at monobasic and by two pharmaceutical companies. NARC-1 was identified via dibasic residues. The recently characterized pyrolysin-like subtilase the cloning of cDNAs up-regulated after apoptosis induced by SKI-1 cleaves proproteins at nonbasic residues. In this work we serum deprivation in primary cerebellar neurons, whereas LP251 describe the properties of a proteinase K-like subtilase, neural was discovered via global cloning of secretory proteins. Aside apoptosis-regulated convertase 1 (NARC-1), representing the ninth from the fact that NARC-1 mRNA is expressed in liver ϾϾ member of the secretory subtilase family. Biosynthetic and micro- testis Ͼ kidney and that the gene localizes to human chromo- sequencing analyses of WT and mutant enzyme revealed that some 1p33-p34.3, no information is available on NARC-1 ac- human and mouse pro-NARC-1 are autocatalytically and intramo- tivity, cleavage specificity, cellular and tissue expression, and lecularly processed into NARC-1 at the (Y,I)VV(V,L)(L,M)2 motif, a biological function.
    [Show full text]
  • (12) United States Patent (10) Patent No.: US 6,395,889 B1 Robison (45) Date of Patent: May 28, 2002
    USOO6395889B1 (12) United States Patent (10) Patent No.: US 6,395,889 B1 Robison (45) Date of Patent: May 28, 2002 (54) NUCLEIC ACID MOLECULES ENCODING WO WO-98/56804 A1 * 12/1998 ........... CO7H/21/02 HUMAN PROTEASE HOMOLOGS WO WO-99/0785.0 A1 * 2/1999 ... C12N/15/12 WO WO-99/37660 A1 * 7/1999 ........... CO7H/21/04 (75) Inventor: fish E. Robison, Wilmington, MA OTHER PUBLICATIONS Vazquez, F., et al., 1999, “METH-1, a human ortholog of (73) Assignee: Millennium Pharmaceuticals, Inc., ADAMTS-1, and METH-2 are members of a new family of Cambridge, MA (US) proteins with angio-inhibitory activity', The Journal of c: - 0 Biological Chemistry, vol. 274, No. 33, pp. 23349–23357.* (*) Notice: Subject to any disclaimer, the term of this Descriptors of Protease Classes in Prosite and Pfam Data patent is extended or adjusted under 35 bases. U.S.C. 154(b) by 0 days. * cited by examiner (21) Appl. No.: 09/392, 184 Primary Examiner Ponnathapu Achutamurthy (22) Filed: Sep. 9, 1999 ASSistant Examiner William W. Moore (51) Int. Cl." C12N 15/57; C12N 15/12; (74) Attorney, Agent, or Firm-Alston & Bird LLP C12N 9/64; C12N 15/79 (57) ABSTRACT (52) U.S. Cl. .................... 536/23.2; 536/23.5; 435/69.1; 435/252.3; 435/320.1 The invention relates to polynucleotides encoding newly (58) Field of Search ............................... 536,232,235. identified protease homologs. The invention also relates to 435/6, 226, 69.1, 252.3 the proteases. The invention further relates to methods using s s s/ - - -us the protease polypeptides and polynucleotides as a target for (56) References Cited diagnosis and treatment in protease-mediated disorders.
    [Show full text]
  • Foreign Gene Expression in Yeast: a Review
    YEAST VOL. 8: 423-488 (1992) Foreign Gene Expression in Yeast: a Review MICHAEL A. ROMANOS, CAROL A. SCORER AND JEFFREY J. CLARE Department of Cell Biology, Wellcome Research Laboratories. Beckenham, Kent BR3 3BS, U.K. Received 14 February 1992; accepted 22 February 1992 CONTENTS Expression in non-Saccharomyces yeasts Introduction Introduction Pichia pastoris Transformation and selectable markers Hansenula polymorpha Auxotrophic selection markers Kluyveromyces lactis Dominant selectable markers Yarrowia lipolytica Autoselection Schizosaccharomyces pombe Episomal vectors Physiology of foreign gene expression ARS vectors Mechanisms of toxicity 2pbased vectors Generation of low-expressingvariants Regulated copy number vectors Large-scale fermentation and Integrating vectors optimization YIP vectors Concluding remarks Transplacement Acknowledgements Integration into reiterated DNA References Transposition vectors Transcriptional promoters and terminators Foreign versus yeast promoters INTRODUCTION Glycolytic promoters Galactose-regulated promoters The yeast Saccharomyces cerevisiae has several Phosphate-regulated promoters properties which have established it as an important Glucose-repressible promoters tool in theexpressionofforeign protein sfor research, Other regulated promoter systems industrial or medical use. As a food organism, it Selection of novel yeast promoters is highly acceptable for the production of pharma- Foreign promoter systems ceutical proteins. In contrast, Escherichia coli has Yeast terminators toxic cell wall pyrogens and mammalian cells may contain oncogenic or viral DNA, so that products Factors affecting intracellular expression Initiation of transcription from these organisms must be tested more exten- RNA elongation sively. Yeast can be grown rapidly on simple media RNA stability and to high cell density, and its genetics are more Initiation of translation advanced than any other eukaryote, so that it can be Translational elongation manipulated almost as readily as E.coli.
    [Show full text]
  • Chymotrypsin-Like Peptidases in Insects
    Chymotrypsin-like peptidases in insects Dissertation zur Erlangung des akademischen Grades Doctor rerum naturalium (Dr. rer. nat.) Fachbereich Biologie/Chemie der Universität Osnabrück vorgelegt von Gunnar Bröhan Osnabrück, Mai 2010 TABLE OF CONTENTS I Table of contents 1. Introduction 1 1.1. Serine endopeptidases 1 1.2. The structure of S1A chymotrypsin-like peptidases 2 1.3. Catalytic mechanism of chymotrypsin-like peptidases 6 1.4. Insect chymotrypsin-like peptidases 9 1.4.1. Chymotrypsin-like peptidases in insect immunity 9 1.4.2. Role of chymotrypsin-like peptidases in digestion 14 1.4.3. Involvement of chymotrypsin-like peptidases in molt 16 1.5. Objective of the work 18 2. Material and Methods 20 2.1. Material 20 2.1.1. Culture Media 20 2.1.2. Insects 20 2.2. Molecular biological methods 20 2.2.1. Tissue preparations for total RNA isolation 20 2.2.2. Total RNA isolation 21 2.2.3. Reverse transcription 21 2.2.4. Quantification of nucleic acids 21 2.2.5. Chemical competent Escherichia coli 21 2.2.6. Ligation and transformation in E. coli 21 2.2.7. Preparation of plasmid DNA 22 2.2.8. Restriction enzyme digestion of DNA 22 2.2.9. DNA gel-electrophoresis and DNA isolation 22 2.2.10. Polymerase-chain-reaction based methods 23 2.2.10.1. RACE-PCR 23 2.2.10.2. Quantitative Realtime PCR 23 2.2.10.3. Megaprimer PCR 24 2.2.11. Cloning of insect CTLPs 25 2.2.12. Syntheses of Digoxigenin-labeled DNA and RNA probes 26 2.2.13.
    [Show full text]
  • Structural and Biochemical Characterizations of Three Potential Drug Targets from Pathogens
    Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 2020 Structural and Biochemical Characterizations of Three Potential Drug Targets from Pathogens LU LU ACTA UNIVERSITATIS UPSALIENSIS ISSN 1651-6214 ISBN 978-91-513-1148-7 UPPSALA urn:nbn:se:uu:diva-435815 2021 Dissertation presented at Uppsala University to be publicly examined in Room A1:111a, BMC, Husargatan 3, Uppsala, Friday, 16 April 2021 at 13:15 for the degree of Doctor of Philosophy. The examination will be conducted in English. Faculty examiner: Christian Cambillau. Abstract Lu, L. 2021. Structural and Biochemical Characterizations of Three Potential Drug Targets from Pathogens. Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 2020. 91 pp. Uppsala: Acta Universitatis Upsaliensis. ISBN 978-91-513-1148-7. As antibiotic resistance of various pathogens emerged globally, the need for new effective drugs with novel modes of action became urgent. In this thesis, we focus on infectious diseases, e.g. tuberculosis, malaria, and nosocomial infections, and the corresponding causative pathogens, Mycobacterium tuberculosis, Plasmodium falciparum, and the Gram-negative ESKAPE pathogens that underlie so many healthcare-acquired diseases. Following the same- target-other-pathogen (STOP) strategy, we attempted to comprehensively explore the properties of three promising drug targets. Signal peptidase I (SPase I), existing both in Gram-negative and Gram-positive bacteria, as well as in parasites, is vital for cell viability, due to its critical role in signal peptide cleavage, thus, protein maturation, and secreted protein transport. Three factors, comprising essentiality, a unique mode of action, and easy accessibility, make it an attractive drug target.
    [Show full text]
  • Effects of Glycosylation on the Enzymatic Activity and Mechanisms of Proteases
    International Journal of Molecular Sciences Review Effects of Glycosylation on the Enzymatic Activity and Mechanisms of Proteases Peter Goettig Structural Biology Group, Faculty of Molecular Biology, University of Salzburg, Billrothstrasse 11, 5020 Salzburg, Austria; [email protected]; Tel.: +43-662-8044-7283; Fax: +43-662-8044-7209 Academic Editor: Cheorl-Ho Kim Received: 30 July 2016; Accepted: 10 November 2016; Published: 25 November 2016 Abstract: Posttranslational modifications are an important feature of most proteases in higher organisms, such as the conversion of inactive zymogens into active proteases. To date, little information is available on the role of glycosylation and functional implications for secreted proteases. Besides a stabilizing effect and protection against proteolysis, several proteases show a significant influence of glycosylation on the catalytic activity. Glycans can alter the substrate recognition, the specificity and binding affinity, as well as the turnover rates. However, there is currently no known general pattern, since glycosylation can have both stimulating and inhibiting effects on activity. Thus, a comparative analysis of individual cases with sufficient enzyme kinetic and structural data is a first approach to describe mechanistic principles that govern the effects of glycosylation on the function of proteases. The understanding of glycan functions becomes highly significant in proteomic and glycomic studies, which demonstrated that cancer-associated proteases, such as kallikrein-related peptidase 3, exhibit strongly altered glycosylation patterns in pathological cases. Such findings can contribute to a variety of future biomedical applications. Keywords: secreted protease; sequon; N-glycosylation; O-glycosylation; core glycan; enzyme kinetics; substrate recognition; flexible loops; Michaelis constant; turnover number 1.
    [Show full text]
  • Serine Proteases with Altered Sensitivity to Activity-Modulating
    (19) & (11) EP 2 045 321 A2 (12) EUROPEAN PATENT APPLICATION (43) Date of publication: (51) Int Cl.: 08.04.2009 Bulletin 2009/15 C12N 9/00 (2006.01) C12N 15/00 (2006.01) C12Q 1/37 (2006.01) (21) Application number: 09150549.5 (22) Date of filing: 26.05.2006 (84) Designated Contracting States: • Haupts, Ulrich AT BE BG CH CY CZ DE DK EE ES FI FR GB GR 51519 Odenthal (DE) HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI • Coco, Wayne SK TR 50737 Köln (DE) •Tebbe, Jan (30) Priority: 27.05.2005 EP 05104543 50733 Köln (DE) • Votsmeier, Christian (62) Document number(s) of the earlier application(s) in 50259 Pulheim (DE) accordance with Art. 76 EPC: • Scheidig, Andreas 06763303.2 / 1 883 696 50823 Köln (DE) (71) Applicant: Direvo Biotech AG (74) Representative: von Kreisler Selting Werner 50829 Köln (DE) Patentanwälte P.O. Box 10 22 41 (72) Inventors: 50462 Köln (DE) • Koltermann, André 82057 Icking (DE) Remarks: • Kettling, Ulrich This application was filed on 14-01-2009 as a 81477 München (DE) divisional application to the application mentioned under INID code 62. (54) Serine proteases with altered sensitivity to activity-modulating substances (57) The present invention provides variants of ser- screening of the library in the presence of one or several ine proteases of the S1 class with altered sensitivity to activity-modulating substances, selection of variants with one or more activity-modulating substances. A method altered sensitivity to one or several activity-modulating for the generation of such proteases is disclosed, com- substances and isolation of those polynucleotide se- prising the provision of a protease library encoding poly- quences that encode for the selected variants.
    [Show full text]
  • And SPP-Like Proteases☆
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Biochimica et Biophysica Acta 1828 (2013) 2828–2839 Contents lists available at ScienceDirect Biochimica et Biophysica Acta journal homepage: www.elsevier.com/locate/bbamem Review Mechanism, specificity, and physiology of signal peptide peptidase (SPP) and SPP-like proteases☆ Matthias Voss a, Bernd Schröder c, Regina Fluhrer a,b,⁎ a Adolf Butenandt Institute for Biochemistry, Ludwig-Maximilians University Munich, Schillerstr. 44, 80336 Munich, Germany b DZNE — German Center for Neurodegenerative Diseases, Munich, Schillerstr. 44, 80336 Munich, Germany c Biochemical Institute, Christian-Albrechts-University Kiel, Olshausenstrasse 40, 24118 Kiel, Germany article info abstract Article history: Signal peptide peptidase (SPP) and the homologous SPP-like (SPPL) proteases SPPL2a, SPPL2b, SPPL2c and Received 27 December 2012 SPPL3 belong to the family of GxGD intramembrane proteases. SPP/SPPLs selectively cleave transmembrane Received in revised form 25 March 2013 domains in type II orientation and do not require additional co-factors for proteolytic activity. Orthologues of Accepted 29 March 2013 SPP and SPPLs have been identified in other vertebrates, plants, and eukaryotes. In line with their diverse subcellular localisations ranging from the ER (SPP, SPPL2c), the Golgi (SPPL3), the plasma membrane Keywords: (SPPL2b) to lysosomes/late endosomes (SPPL2a), the different members of the SPP/SPPL family seem to Regulated intramembrane proteolysis fi Intramembrane-cleaving proteases exhibit distinct functions. Here, we review the substrates of these proteases identi ed to date as well as GxGD proteases the current state of knowledge about the physiological implications of these proteolytic events as deduced Signal peptide peptidase from in vivo studies.
    [Show full text]
  • Proteolytic Enzymes in Grass Pollen and Their Relationship to Allergenic Proteins
    Proteolytic Enzymes in Grass Pollen and their Relationship to Allergenic Proteins By Rohit G. Saldanha A thesis submitted in fulfilment of the requirements for the degree of Masters by Research Faculty of Medicine The University of New South Wales March 2005 TABLE OF CONTENTS TABLE OF CONTENTS 1 LIST OF FIGURES 6 LIST OF TABLES 8 LIST OF TABLES 8 ABBREVIATIONS 8 ACKNOWLEDGEMENTS 11 PUBLISHED WORK FROM THIS THESIS 12 ABSTRACT 13 1. ASTHMA AND SENSITISATION IN ALLERGIC DISEASES 14 1.1 Defining Asthma and its Clinical Presentation 14 1.2 Inflammatory Responses in Asthma 15 1.2.1 The Early Phase Response 15 1.2.2 The Late Phase Reaction 16 1.3 Effects of Airway Inflammation 16 1.3.1 Respiratory Epithelium 16 1.3.2 Airway Remodelling 17 1.4 Classification of Asthma 18 1.4.1 Extrinsic Asthma 19 1.4.2 Intrinsic Asthma 19 1.5 Prevalence of Asthma 20 1.6 Immunological Sensitisation 22 1.7 Antigen Presentation and development of T cell Responses. 22 1.8 Factors Influencing T cell Activation Responses 25 1.8.1 Co-Stimulatory Interactions 25 1.8.2 Cognate Cellular Interactions 26 1.8.3 Soluble Pro-inflammatory Factors 26 1.9 Intracellular Signalling Mechanisms Regulating T cell Differentiation 30 2 POLLEN ALLERGENS AND THEIR RELATIONSHIP TO PROTEOLYTIC ENZYMES 33 1 2.1 The Role of Pollen Allergens in Asthma 33 2.2 Environmental Factors influencing Pollen Exposure 33 2.3 Classification of Pollen Sources 35 2.3.1 Taxonomy of Pollen Sources 35 2.3.2 Cross-Reactivity between different Pollen Allergens 40 2.4 Classification of Pollen Allergens 41 2.4.1
    [Show full text]
  • Structure of the Human Signal Peptidase Complex Reveals the Determinants for Signal Peptide Cleavage
    bioRxiv preprint doi: https://doi.org/10.1101/2020.11.11.378711; this version posted November 11, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Structure of the Human Signal Peptidase Complex Reveals the Determinants for Signal Peptide Cleavage A. Manuel Liaci1, Barbara Steigenberger2,3, Sem Tamara2,3, Paulo Cesar Telles de Souza4, Mariska Gröllers-Mulderij1, Patrick Ogrissek1,5, Siewert J. Marrink4, Richard A. Scheltema2,3, Friedrich Förster1* Abstract The signal peptidase complex (SPC) is an essential membrane complex in the endoplasmic reticulum (ER), where it removes signal peptides (SPs) from a large variety of secretory pre-proteins with exquisite specificity. Although the determinants of this process have been established empirically, the molecular details of SP recognition and removal remain elusive. Here, we show that the human SPC exists in two functional paralogs with distinct proteolytic subunits. We determined the atomic structures of both paralogs using electron cryo- microscopy and structural proteomics. The active site is formed by a catalytic triad and abuts the ER membrane, where a transmembrane window collectively formed by all subunits locally thins the bilayer. This unique architecture generates specificity for thousands of SPs based on the length of their hydrophobic segments. Keywords Signal Peptidase Complex, Signal Peptide, Protein Maturation, Membrane Thinning, cryo-EM, Crosslinking Mass Spectrometry, Molecular Dynamics Simulations, Protein Secretion, ER Translocon 1Cryo-Electron Microscopy, Bijvoet Centre for Biomolecular Research, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands.
    [Show full text]
  • Trypsinogen Isoforms in the Ferret Pancreas Eszter Hegyi & Miklós Sahin-Tóth
    www.nature.com/scientificreports OPEN Trypsinogen isoforms in the ferret pancreas Eszter Hegyi & Miklós Sahin-Tóth The domestic ferret (Mustela putorius furo) recently emerged as a novel model for human pancreatic Received: 29 June 2018 diseases. To investigate whether the ferret would be appropriate to study hereditary pancreatitis Accepted: 25 September 2018 associated with increased trypsinogen autoactivation, we purifed and cloned the trypsinogen isoforms Published: xx xx xxxx from the ferret pancreas and studied their functional properties. We found two highly expressed isoforms, anionic and cationic trypsinogen. When compared to human cationic trypsinogen (PRSS1), ferret anionic trypsinogen autoactivated only in the presence of high calcium concentrations but not in millimolar calcium, which prevails in the secretory pathway. Ferret cationic trypsinogen was completely defective in autoactivation under all conditions tested. However, both isoforms were readily activated by enteropeptidase and cathepsin B. We conclude that ferret trypsinogens do not autoactivate as their human paralogs and cannot be used to model the efects of trypsinogen mutations associated with human hereditary pancreatitis. Intra-pancreatic trypsinogen activation by cathepsin B can occur in ferrets, which might trigger pancreatitis even in the absence of trypsinogen autoactivation. Te digestive protease precursor trypsinogen is synthesized and secreted by the pancreas to the duodenum where it becomes activated to trypsin1. Te activation process involves limited proteolysis of the trypsinogen activation peptide by enteropeptidase, a brush-border serine protease specialized for this sole purpose. Te activation peptide is typically an eight amino-acid long N-terminal sequence, which contains a characteristic tetra-aspartate motif preceding the activation site peptide bond, which corresponds to Lys23-Ile24 in human trypsinogens.
    [Show full text]
  • Supplementary Data
    Supplementary Fig. 1 A B Responder_Xenograft_ Responder_Xenograft_ NON- NON- Lu7336, Vehicle vs Lu7466, Vehicle vs Responder_Xenograft_ Responder_Xenograft_ Sagopilone, Welch- Sagopilone, Welch- Lu7187, Vehicle vs Lu7406, Vehicle vs Test: 638 Test: 600 Sagopilone, Welch- Sagopilone, Welch- Test: 468 Test: 482 Responder_Xenograft_ NON- Lu7860, Vehicle vs Responder_Xenograft_ Sagopilone, Welch - Lu7558, Vehicle vs Test: 605 Sagopilone, Welch- Test: 333 Supplementary Fig. 2 Supplementary Fig. 3 Supplementary Figure S1. Venn diagrams comparing probe sets regulated by Sagopilone treatment (10mg/kg for 24h) between individual models (Welsh Test ellipse p-value<0.001 or 5-fold change). A Sagopilone responder models, B Sagopilone non-responder models. Supplementary Figure S2. Pathway analysis of genes regulated by Sagopilone treatment in responder xenograft models 24h after Sagopilone treatment by GeneGo Metacore; the most significant pathway map representing cell cycle/spindle assembly and chromosome separation is shown, genes upregulated by Sagopilone treatment are marked with red thermometers. Supplementary Figure S3. GeneGo Metacore pathway analysis of genes differentially expressed between Sagopilone Responder and Non-Responder models displaying –log(p-Values) of most significant pathway maps. Supplementary Tables Supplementary Table 1. Response and activity in 22 non-small-cell lung cancer (NSCLC) xenograft models after treatment with Sagopilone and other cytotoxic agents commonly used in the management of NSCLC Tumor Model Response type
    [Show full text]