DOCSLIB.ORG

A Cycle of Deprotonation and Reprotonation Energizing Amino-Acid Transport? (Diamino Acids/H+ Cotransport/Proton Gradients/Plasma Membrane/Ehrlich Cell)

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
A Cycle of Deprotonation and Reprotonation Energizing Amino-Acid Transport? (Diamino Acids/H+ Cotransport/Proton Gradients/Plasma Membrane/Ehrlich Cell) Proc. Nat. Acad. Sci. USA Vol. 72, No. 1, pp. 23-27, January 1975 A Cycle of Deprotonation and Reprotonation Energizing Amino-Acid Transport? (diamino acids/H+ cotransport/proton gradients/plasma membrane/Ehrlich cell) HALVOR N. CHRISTENSEN AND MARY E. HANDLOGTEN Department of Biological Chemistry, University of Michigan, Ann Arbor, Mich. 48104 Communicated by J. L. Oncley, September 23, 1974 ABSTRACT Although lowering the pK2 of neutral Uptake of the lower homologs of lysine and ornithine amino acids only weakens their concentrative uptake by Ehrlich cells, the same change greatly enhances uptake of By chance we encountered in 1952 behavior revealing that diamino acids. This effect does not arise merely from the data of Table 1 and Fig. 1 do not tell the whole story of the putting the distal amino group in its uncharged form, but role of dissociation in amino-acid transport (18). The struc- depends on an enhanced deprotonation of the a-amino group. Parallel effects are seen for the transport system tural feature responsible for this behavior was a nearness of a for basic amino acids, for which the assignment of pK second amino group to the a-amino group. In the homologous values within the membrane is less ambiguous. To explain series of a,-diamino acids composed of lysine, ornithine, the paradoxical advantages of having the a-amino group 2,4-diaminobutyric acid (A2bu), and 2,3-diaminopropionic protonated yet readily deprotonated, we propose that a acid, we observed an increase in the rate of proton withdrawn from that group is pumped over an abrupt uptake intramembrane interval to energize amino-acid transport. and intensity of accumulation as the chain is shortened to four carbons or less (Fig. 3). The most intensely accumulated Although a driving of amino-acid uptake by cotransport with is A2bu, both for Ehrlich ascites tumor cells and for rat liver Na+ has long been known (1-4), this has recently been shown (18). Almost all of the endogenous levels of K+ and Na+ not to be the obligatory mode of energization (5). Further- could be displaced from the Ehrlich cell by this organic cation, more, Na+-independent systems can unambiguously produce its uptake along with Cl- having in the meantime caused the uphill transport (5). Therefore, we have long given attention cells to swell to two to four times their normal volume during to suggestive effects of modifying the H+-dissociation of the several hours. Gradients as high as 180 mAM could be obtained amino acids as clues to a more fundamental mode of energiza- when uptake occurred from hypertonic solution, thus mini- tion (ref. 5; ref. 6, pp. 91-92; refs. 7-9). mizing simultaneous water transfer. Table 1 illustrates that a systematic lowering of pK2' of The principal difference among these diamino acids lies not neutral amino acids (in this case by introducing one, two, or in the rates at which they are accumulated by the cationic three fluorine atoms) decreases both the initial rate of uptake amino-acid system, for which their Km values are relatively and the steady-state distribution attained with Ehrlich low, but in their reactivities at high Km values with ascites tumor cells. Fig. 1 shows a corresponding effect of the systems for neutral amino acids. When we contrasted the presence of two fluorine atoms in the amino-acid molecule: concentration dependence of the uptake of lysine and A2bu by the pH optimum for uptake is lowered sharply. These results Ehrlich cells, we saw similar hyperbolic portions for the curves indicate that the amino acid is accepted for uptake by the at low levels, representing uptake by the cationic system, system in question with the amino group in the form RNH3+ inhibitable by homoarginine. At higher levels we noted a rather than RNH2. component that was difficult to saturate, much larger for This result did not prove, however, that the recognition A2bu than for lysine. An inhibition analysis showed that this site at the interior surface of the membrane has the same component for A2bu and for diaminopropionate occurs by preference. In 1958 we considered, using Fig. 2, whether a System A and is Na+-dependent (19). This was a surprising difference in the state of protonation preferred at the two result, because that system ordinarily has neutral amino surfaces might produce co- or countertransport of H+ with acids for its substrates (20). the amino acid (3). The figure shows a hydrogen ion left We begin in this way to encounter a series of paradoxes. behind when the amino acid combines with the external Even though A2bu, pK2 = 8.4, should be cationic to the receptor site, and a new hydrogen ion taken up by the amino extent of 91% at pH 7.4, most of its uptake at high levels acid on entering the cytoplasm. This scheme produces a occurs by a neutral amino-acid system. Of the 9% that is countertransport between H+ and the amino acid, which was present in dipolar form in water solution at that pH, a major in 1958 an arbitrary choice over cotransport. Possibilities of part takes the form of the a,-y-dipolar ion, by analogy not a this kind have subsequently become more important through substrate for a transport system for a-amino acids. The the development by Mitchell of his chemiosmotic hypothesis values for pK2' for the homologous series of Fig. 3 in order of for the intermediation of hydrogen ion gradients in the process decreasing chain length, are 9.5, 8.7, 8.4, and 6.8. The initial of energy transduction by the mitochondrial and chloroplast rates of uptake increase as pK2' decreases, just the reverse membrane (11, 12). The observation of cotransport of H+ of the order shown in Table 1 for monoamnino acids in the same with amino acids (see for example refs. 8 and 13) and with transport system. sugars (14-16) has accelerated the extension of these ideas to The latter paradox becomes not quite so implausible when the plasma membrane (see ref. 17). one considers that for transport these diamino acids need to lose a proton to convert their cationic form to a dipolar species. Abbreviation: A2bu, L-2,4-diaminobutyric acid. One might expect that A2bu could become as good a substrate 23 Downloaded by guest on September 28, 2021 24 Biochemistry: Christensen and Handlogten Proc. Nat. Acad. Sci. USA 72 (1975) ? 1.6 0.2 TABLE 1. Effect of 3-fluoro substitution on transport of x 2-aminoisobutyric acid into the Ehrlich cell D 1.2 (scaleatright Distribution ratio co 0.8 - (scale at left) 0.1 for Ehrlich cell 750-0 pK'/ 0) Substrate (250) at 1 min at 30 min a 0.4 Aminoisobutyric acid, 1 mM 10.21 0.85 27.7 E E 0~ Fluoroaminoisobutyric acid, :: 6 7 8 1 mM 8.58 0.95 13.0 PHex Difluoroaminoisobutyric acid, FIG. 1. Effect of the presence of two fluorine atoms in 2- 3mM 7.40 0.17 3.6 aminoisobutyric acid on the pH optimum for the rate of uptake Trifluoroaminoisobutyric acid, by Ehrlich ascites tumor cells. Uptake observed during 2 min at 1 mM 5.94 0.27 0.74 370 from Krebs-Ringer phosphate solution, adjusted to give the final pH shown. Presumably, the increasing quantity of this Difluoroaminoisobutyric acid is the symmetrical difluoro amino acid in its dipolar form compensates in part for the de- derivative, prepared from 1,5-difluoro-3-pentanone by the same crease in rate that would otherwise occur below pH 7.4. *, 0.2 procedure used for the monofluoro derivative. At 30 min, its mM difluoroaminoisobutyric acid; 0, 0.2 mM aminoisobutyric distribution ratio was at the maximum value. In trifluoroiso- acid. butyric acid, the fluorine atoms are all on the same carbon atom. The transport disadvantage of the fluoro analogs applies also to for System A as homoserine, once it has lost a proton, given renal resorption and hepatic uptake (10). only that this proton be lost from the distal amino group. But now the paradox reappears: A2bu is far more strongly stabilization of a species unsuitable for transport by the accumulated by the Ehrlich cell than is homoserine (Fig. 3). inner receptor site is not shared by the outer receptor site. Why should these diamino acids act as "super-substrates," To show that the two opposed transport receptor sites given their special difficulty in assuming the preferred struc- place the substrate in dissimilar electrostatic environments ture for uptake? Even though A2bu can assume this structure would not provide a sufficient explanation of the flux asym- more readily than ornithine, which can assume it more readily metry, however, unless we add an energy input to maintain the than lysine, all of these amino acids should be at a handicap environmental difference, whatever it is. Under the simple in comparison with homoserine or other ordinary neutral model implied here, energy would have to be applied steadily amino acids. Clearly, the ability of the amino acids to assume to keep changing the environment of the site for entry into the statically their a,a-dipolar form by no means provides a full membrane to an environment suitable for release into the explanation of the effects of changes in the pK values. cytoplasm. Let us examine, then, the possibilities introduced along with We early began to attribute the contrast in transport a second amino group. We may propose, first of all, that the among the diamino acids to the inductive interactions be- receptor site for entry provides a microenvironment for the tween the two amino groups.
Load more

Recommended publications
  • From a Pseudomonad, Catalyzes the Oxygenation of L-Lysi an A,E
    Proc. Nat. Acad. Sci. USA Vol. 69, No. 12, pp. 3723-3726, December 1972 Alkylamine-Dependent Amino-Acid Oxidation by Lysine Monooxygenase- Fragmented Substrate of Oxygenase (Pseudomonas/enzyme/aminefamide/flavoprotein) SHOZO YAMAMOTO, TAKASHI YAMAUCHI, AND OSAMU HAYAISHI Department of Medical Chemistry, Kyoto University Faculty of Medicine, Kyoto, Japan Contributed by Osamu Hayaishi, October 10, 1972d ABSTRACT Lysine monooxygenase catalyzes the cIxy- a significant role in the catalysis of the enzyme. It would be of a rre- genative decarboxylation of L-lysine and produces coi heefoeto investigate the reaction of the enzyme sponding acid amide. L-Alanine was inactive as substriate. However, when propylamine was present, oxidation,Ibut in the presence of both a-monoamino acids and alkylamines- not oxygenation, of alanine was demonstrated with the of various carbon chain lengths-the two fragments of the oxygenase. Alanine was converted to pyruvate, with the normal substrate. liberation of ammonia and hydrogen peroxide, but proyI~yl- amine remained unchanged. Other a-monoamino accids MATERIALS AND METHODS were also oxidized in the presence of alkylamines wi various carbon chain lengths. The highest oxidase actiiV~it Lysine monooxygenase was purified and assayed as described was observed when the total chain length of both anm Lio (1). Pyruvate was determined with the aid of rabbit-muscle acid and amine was nearly identical with that of lysiine, lactate dehydrogenase Type II (Sigma) (4) or as its hydrazone Available evidence indicates that the amine-depend,lent (5). Oxygen consumption was followed by an oxygen electrode 5ine amino-acid oxidase activity is associated with the lys (1). As the solubility of oxygen in water decreases when the oxygenase activity.
    [Show full text]
  • Solid Phase Synthesis and RNA-Binding Activity of an Arginine-Containing Nucleopeptide† Cite This: RSC Adv.,2016,6, 14140 G
    RSC Advances View Article Online PAPER View Journal | View Issue Solid phase synthesis and RNA-binding activity of an arginine-containing nucleopeptide† Cite this: RSC Adv.,2016,6, 14140 G. N. Roviello,*a C. Vicidomini,a S. Di Gaetano,a D. Capasso,b D. Musumeciac and V. Roviellod Here we report the solid phase synthesis and characterization (LC-ESIMS, CD) of a cationic nucleobase- containing a-peptide, composed of both L-arginine residues and L-lysine-based nucleoamino acids sequentially present in the structure. The binding properties of this novel basic nucleopeptide towards nucleic acids were investigated by CD spectroscopy which revealed the ability of the thymine-containing Received 3rd December 2015 oligomer to bind both adenine-containing DNA (dA ) and RNA (poly rA) molecules inducing high Accepted 15th January 2016 12 conformational variations in the nucleic acid structures. Moreover, the artificial oligonucleotide inhibited DOI: 10.1039/c5ra25809j the enzymatic activity of HIV reverse transcriptase, opening the door to the exploitation of novel antiviral www.rsc.org/advances strategies inspired to this molecular tool. Creative Commons Attribution-NonCommercial 3.0 Unported Licence. Introduction oligonucleotides with high sequence specicity.14,15 With respect to other building blocks used for the realization of articial Numerous investigations have shown that the sugar- nucleopeptides, diamino acids offer easy synthetic routes for phosphodiester backbone of the nucleic acids can be variously decorating with nucleobases the main
    [Show full text]
  • Amino Acids and the Asymmetry of Life; Springer, 2008.Pdf
    Amino Acids and the Asymmetry of Life Advances in Astrobiology and Biogeophysics springer.com This series aims to report new developments in research and teaching in the inter- disciplinary fields of astrobiology and biogeophysics. This encompasses all aspects of research into the origins of life – from the creation of matter to the emergence of complex life forms – and the study of both structure and evolution of planetary ecosystems under a given set of astro- and geophysical parameters. The methods con- sidered can be of theoretical, computational, experimental and observational nature. Preference will be given to proposals where the manuscript puts particular emphasis on the overall readability in view of the broad spectrum of scientific backgrounds involved in astrobiology and biogeophysics. The type of material considered for publication includes: • Topical monographs • Lectures on a new field, or presenting a new angle on a classical field • Suitably edited research reports • Compilations of selected papers from meetings that are devoted to specific topics The timeliness of a manuscript is more important than its form which may be un- finished or tentative. Publication in this new series is thus intended as a service to the international scientific community in that the publisher, Springer-Verlag, offers global promotion and distribution of documents which otherwise have a restricted readership. Once published and copyrighted, they can be documented in the scientific literature. Series Editors: Dr. André Brack Dr. Christopher P. McKay Centre de Biophysique Moléculaire NASA Ames Research Center CNRS, Rue Charles Sadron Moffet Field 45071 Orléans, Cedex 2, France CA 94035,USA [email protected] Dr.
    [Show full text]
  • 297 1963A 119 A'hearn Michael F. 22, 42, 59, 62, 71–73, 80, 82, 105, 109, 113, 116, 195, 215, 264 Absolute Asymmetric Photoc
    297 Index a β-alanine 1963a 119 – in simulated interstellar ices 146 A’Hearn Michael F. 22, 42, 59, 62, 71–73, – photoformation of 174 80, 82, 105, 109, 113, 116, 195, 215, albedo 264 –definition 43 absolute asymmetric photochemistry 169, – geometric 43 176 – of (21) Lutetia 220 absolute asymmetric photolysis 167, 169 – of (2867) Šteins 214 absolute asymmetric synthesis 165, 174 – of 103P/Hartley 81 absorption 168 – of 19P/Borrelly 52 acetaldehyde 110, 267 – of 1P/Halley 6, 43 acetic acid 267 – of 67P/Churyumov-Gerasimenko 199 acetonitrile 267 – of 81P/Wild 2, 65 acetylene 112 – of 9P/Tempel 1 71, 78 acid hydrolysis – of asphalt 6 –ofStardustsamples 64 –spherical 43 acoustic sounding 272 Alenia Spazio 234 aegPNA 152 ALICE aerogel 55, 57, 59–64, 102, 251 – flight model 243 Ag-black 251 – INVESTIGATIONS ON (21) LUTETIA 26Al 221 – β+-radiator 179 – investigations on (21) Lutetia 220 26Al 136, 137, 150, 202 – investigations on (2867) Šteins 215 – β+-radiator 180 – investigations on 67P/C-G 241 alanine – microchannel plate detector 242 – anisotropy spectrum 171, 173 – on 67P/C-G formation temperature 244 – circular dichroism spectrum 171 – on 67P/C-G H2O, CO, and CO2 244 – early-recruited in protein 152 – on 67P/C-G noble gases 244 – enantioselective photolysis of 172 – on 67P/C-G O+ and C+ 245 – from impact shock synthesis 151 – operation during Mars swing-by 209 –GC×GC analysis of 173 Allamandola, Louis 143, 174 – in simulated interstellar ices 143, 146 allo-2-amino-2,3-dimethylpentanoic acid – in Stardust’s witness aerogel 63 – meteoritic e.e.
    [Show full text]
  • The Synthesis of Protein with an Identification Peptide
    European Patent Office © Publication number: 0 150 126 Office europeen des brevets A2 © EUROPEAN PATENT APPLICATION N 15/00 © Application number: 85300432.3 ©Int CI.-: C 12 C 12 P 21/00, C 12 N 5/00 © Date of filing: 23.01.% C 07 K 1/00 ® Priority: 24.01.84 US 573825 © Inventor: Hopp, Thomas P. 48425stS.W. Seattle Washington 981 16(US) © Date of publication of application : 31.07.85 Bulletin 86/31 © Inventor: Bektesh, Susan L. 8711 19th N.W. © Designated Contracting States: Seattle Washington 981 17(US) AT BE CH DE FR GB IT LI NL SE © Inventor: Conlon III, PaulJ. © Applicant: IMMUNEX CORPORATION 4021 N.E.75th 51 University Building Suite 600 Seattle Washington 98115(US) Seattle Washington 98101 (US) © Inventor: March, CartJ. 81338th S.W. Seattle Washington 98106IUS) © Representative: Bizley, Richard Edward et al, BOULT, WADE & TENNANT 27 Furnival Street London EC4A 1PQ(GB) © The synthesis of protein with an identification peptide. ©A A hybrid polypeptide composed of an identification peptide and a desired functional protein are produced by recombinant DNA techniques. A DNA expression vector is constructed that includes segments of DNA coding for the identification peptide and the desired functional protein. The identification peptide consists of a highly antigenic N- terminal portion and a C-terminal linking portion that connects the identification peptide to the N-terminal of the functional protein. The linking portion of the identification peptide is cleavable at a specific amino acid residue adjacent the functional protein by use of a sequence specific proteoly- CM tic enzyme or chemical proteolytic agent.
    [Show full text]
  • (12) Patent Application Publication (10) Pub. No.: US 2005/0038255A1 Thibaut Et Al
    US 20050038255A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2005/0038255A1 Thibaut et al. (43) Pub. Date: Feb. 17, 2005 (54) STEREOSELECTIVE PREPARATION OF (52) U.S. Cl. ............................................ 546/225; 548/530 CYCLIC LAMINO ACIDS (57) ABSTRACT (76) Inventors: Denis Thibaut, Paris (FR); Volker The invention concerns a method for producing a cyclic Doring, Paris (FR); Philippe Marliere, L-amino acid of formula (I), characterised in that it consists Etioles (FR) in reacting a L-diamino acid of formula (II) or an enantio meric mixture comprising Such a L-diamino acid and a Correspondence Address: corresponding D-diamino acid in variable proportions, in the BURNS DOANE SWECKER & MATHIS LLP presence of an ornithine cyclodeaminase or a polypeptide POST OFFICE BOX 1404 homologous to the ornithine cyclodeaminase. ALEXANDRIA, VA 22313-1404 (US) (21) Appl. No.: 10/479,719 (I) (22) PCT Filed: Jun. 10, 2002 X n COOH (86) PCT No.: PCT/FRO2/O1983 R1 (30) Foreign Application Priority Data (II) H S Jun. 8, 2001 (FR)............................................ 01/07559 HRN-X V NH2 Publication Classification COOH (51) Int. Cl. ................................................... C07D 211/30 US 2005/0038255 A1 Feb. 17, 2005 STEREOSELECTIVE PREPARATION OF CYCLC of these enzymes and their level of catalytic activity remain L-AMINO ACIDS unknown even though these are determinant elements for the 0001. The present invention relates to the stereoselective productivity of an enzymatic process. preparation of cyclic L-amino acids or Salts and derivatives 0011 For three of these genes found in Streptomyces, thereof. producers of metabolites derived from L-pipecolic acid, a 0002 There is an increasing demand for cyclic amino lysine cyclodeaminase activity for the encoded polypeptide acids, particularly L-proline, L-pipecolic acid or L-pipera has been postulated (WO-A1-96/01901; L.
    [Show full text]
  • Waste Nitrogen Excretion Via Amino Acid Acylation: Benzoate and Phenylacetate in Lysinuric Protein Intolerance
    003 1-39981861201 1- 1 1 17$02.00/0 PEDIATRIC RESEARCH Vol. 20, No. 11, 1986 Copyright O 1986 International Pediatric Research Foundation. Inc Prinled in (I.S. A. Waste Nitrogen Excretion Via Amino Acid Acylation: Benzoate and Phenylacetate in Lysinuric Protein Intolerance OLLl SIMELL, ILKKA SIPILA, JUKKA RAJANTIE, DAVID L. VALLE, AND SAUL W. BRUSILOW CXildren '.Y Hospital, Universitj9ofl-lelsinki, SF-00290 Helsinki, Finland; and Department of'Pediatrics, The Johns Hopkins Unive,siij~School of Medicine, Baltimore, Maryland 21205 ABSTRACT. Benzoate and phenylacetate improve prog- glutamine, respectively; less than 3.5% appeared un- nosis in inherited urea cycle enzyme deficiencies by increas- changed in urine. (Pediatr Res 20: 1117-1 121, 1986) ing waste nitrogen excretion as amino acid acylation prod- ucts. We studied metabolic changes caused by these sub- Abbreviations stances and their pharmacokinetics in a biochemically different urea cycle disorder, lysinuric protein intolerance LPI, lysinuric protein intolerance (LPI), under strictly standardized induction of hyperam- iv, intravenous monemia. Five patients with LPI received an intravenous infusion of 6.6 mmol/kg L-alanine alone and separately with 2.0 mmollkg of benzoate or phenylacetate in 90 min. Blood for ammonia, serum urea and creatinine, plasma In 19 14, Lewis (I) showed that benzoate modifies waste nitro- benzoate, hippurate, phenylacetate, phenylacetylgluta- gen excretion by decreasing production of urea via excretion of mine, and amino acids was obtained at 0, 120, 180, and waste nitrogen as the acylation product of glycine with benzoate, 270 min. Urine was collected in four consecutive 6-h pe- i.e. hippurate. A few years later (2) phenylacetate was noted to riods.
    [Show full text]
  • Amino Acids and Acid Amides As Sources of Ammonia in Soils
    Research Bulletin No.9 November, 1912 Amino Acids and Acid Amides as Sources Of Ammonia in Soils By S. L. ] odidi AGRICULTURAL EXPERIMENT STATION IOWA STATE COLLEGE OF AGRICULTURE AND THE MECHANIC ARTS AGRONOMY SECTION Soil Chemistry AMES, IOWA OFFICERS AND STAFF IOWA AGRICULTURAL EXPERIMENT STATION ST.\TEl BO.\RD OF EDUCATION Hon. J. IT. Trewin, Ceda!' Rapids. Hon. A. B. Funk, Spirit Lake. Hon. George T. Baker, Davenport. Hon. Charles R. Brenton, Dallas Ccnter. Hon. E. P. Schoentgen, Council Bluffs. Hon. Parker K. Holbrook, Onawa. I-Ion. D. D. Murphy, Elkader. Hon. Roger Leavitt, Cedar Falls. Hon. Hcnr)" 111. Eicher, Washington. OFFICERS Hon. J. H. Trewin, Cedar Rapids ................................ President Hon. D. A. Emery, Ottumwa ................ ............... Secretary FINANCEl CO~iMI'L'TEEl Hon. W. R. Boyd, President, Cedar Rapids. Hon. Thos. Lambert, Sabula. Hon. D ..-\. Emcry, Secretary, Ottumwa. AGRICULTURAL EXPERIMENT STATION STAFF Raymond A. Pearson, M. S. A., LL. D. , President. C. F. Curtiss, lIi. S. A., D. S., Director. W. H. Stevenson, A. B., B. S. A., Vice Director. J. B. Davidson, B. S., M. El. , Chief in Agricultural Engineering. W. II. Stevenson, A. B., B S. A., Chief in Agronomy. H. D. Hughes, 111. S., Chief in If'arm Crops. L. C. Burnett, 111. S. A., Assistant Cbicf in Cereal Breeding. P. E. Brown, B. S., A. lIf., Pb. D., Assistant Cbief in Soil Bacteriology. John Buchanan, B. S. A., Superintendent of Co-operative Elxperiments. Oharles R. IPOl'est, Field Superintendent. E. H. Kellogg, B. S., Assistant in Soil Chemistry. Robt. Snyder, B. S., Assistant in Soil Cbemistry. W.
    [Show full text]
  • Amino Acids and the Asymmetry of Life
    Caught in the Act of Formation: Amino Acids and the Asymmetry of Life Prof. Dr. Uwe Meierhenrich Université de Nice-Sophia Antipolis, France UMR 6001 CNRS, LCMBA NIS Colloquium First chemical steps towards the origin of life Torino, Italy, 16 17 September 2010 t/min Fig. 1. Gas chromatogram of resolved hydrocarbon enantiomers 3-methylheptane, 4-methyloctane, 3-methyloctane, 4-methyl-nonane, 3-methylnonane, and 3-methyldecane separated on a capillary column coated with permethylated -cyclodextrin (Chirasil-Dex CB, 25 m, 0.25 mm inner diameter, layer thickness 0.25µm, Varian-Chrompack). Meierhenrich U.J. et al .: Chirality 15 (2003), S13-S16. How did life originate ? And why were left-handed amino acids selected for its architecture ? 1) Formation of amino acids in interstellar space 2) Diamino acids in interstellar space and in meteorites 3) Chirality: The enantiomeric excess of interstellar amino acids 4) Cometary mission Rosetta Meierhenrich 4 Fig.5: Knots of gas in the Dumbbell Nebular. Dense knots of gas and dust seem to be a natural part of the evolution of planetary Planetary Camera 2 in November 2001. The filters used to create this color image show oxygen in blue, hydrogen in green and a combination of sulfur and nitrogen emission in red. -PRC2003-06 5 Fig.4a: A dark interstellar molecular Fig.4b: Gas collision in the Helix nebular. Image taken by cloud by the passage of a star cluster in the Pleiades. Reflection nebulosity. nitrogen emission ([NII] 6584 A); green, hydrogen ([H-alpha, 6563 A); blue, oxygen (5007 A). Image courtesy of NASA and the Hubble Heritage Team Rice University, NASA STScI-PRC2000-36 Image STScI-PRC1996-13a 6 Brownlee-particles Fig.5a: A Brownlee particlel is composed of Interstellar Fig.5b: An aggregate of interstellar dust Dust is composed of rocky material that are assumed particles.
    [Show full text]
  • From a Pseudomonad, Catalyzes the Oxygenation of L-Lysi an A,E
    Proc. Nat. Acad. Sci. USA Vol. 69, No. 12, pp. 3723-3726, December 1972 Alkylamine-Dependent Amino-Acid Oxidation by Lysine Monooxygenase- Fragmented Substrate of Oxygenase (Pseudomonas/enzyme/aminefamide/flavoprotein) SHOZO YAMAMOTO, TAKASHI YAMAUCHI, AND OSAMU HAYAISHI Department of Medical Chemistry, Kyoto University Faculty of Medicine, Kyoto, Japan Contributed by Osamu Hayaishi, October 10, 1972d ABSTRACT Lysine monooxygenase catalyzes the cIxy- a significant role in the catalysis of the enzyme. It would be of a rre- genative decarboxylation of L-lysine and produces coi heefoeto investigate the reaction of the enzyme sponding acid amide. L-Alanine was inactive as substriate. However, when propylamine was present, oxidation,Ibut in the presence of both a-monoamino acids and alkylamines- not oxygenation, of alanine was demonstrated with the of various carbon chain lengths-the two fragments of the oxygenase. Alanine was converted to pyruvate, with the normal substrate. liberation of ammonia and hydrogen peroxide, but proyI~yl- amine remained unchanged. Other a-monoamino accids MATERIALS AND METHODS were also oxidized in the presence of alkylamines wi various carbon chain lengths. The highest oxidase actiiV~it Lysine monooxygenase was purified and assayed as described was observed when the total chain length of both anm Lio (1). Pyruvate was determined with the aid of rabbit-muscle acid and amine was nearly identical with that of lysiine, lactate dehydrogenase Type II (Sigma) (4) or as its hydrazone Available evidence indicates that the amine-depend,lent (5). Oxygen consumption was followed by an oxygen electrode 5ine amino-acid oxidase activity is associated with the lys (1). As the solubility of oxygen in water decreases when the oxygenase activity.
    [Show full text]
  • From Prebiotic Chemistry to Supramolecular Biomedical Materials: Exploring the Properties of Self-Assembling Nucleobase-Containing Peptides
    molecules Review From Prebiotic Chemistry to Supramolecular Biomedical Materials: Exploring the Properties of Self-Assembling Nucleobase-Containing Peptides Pasqualina Liana Scognamiglio 1,†, Chiara Platella 2,† , Ettore Napolitano 2, Domenica Musumeci 2,3 and Giovanni Nicola Roviello 3,* 1 Center for Advanced Biomaterial for Health Care (CABHC), Istituto Italiano di Tecnologia, I-80125 Naples, Italy; [email protected] 2 Department of Chemical Sciences, University of Naples Federico II, via Cintia 21, I-80126 Naples, Italy; [email protected] (C.P.); [email protected] (E.N.); [email protected] (D.M.) 3 Istituto di Biostrutture e Bioimmagini IBB-CNR, via Tommaso De Amicis 95, I-80145 Naples, Italy * Correspondence: [email protected]; Tel.: +39-0812534585 † These authors contributed equally to this work. Abstract: Peptides and their synthetic analogs are a class of molecules with enormous relevance as therapeutics for their ability to interact with biomacromolecules like nucleic acids and proteins, poten- tially interfering with biological pathways often involved in the onset and progression of pathologies of high social impact. Nucleobase-bearing peptides (nucleopeptides) and pseudopeptides (PNAs) offer further interesting possibilities related to their nucleobase-decorated nature for diagnostic and therapeutic applications, thanks to their reported ability to target complementary DNA and RNA strands. In addition, these chimeric compounds are endowed with intriguing self-assembling Citation: Scognamiglio, P.L.; Platella, properties, which are at the heart of their investigation as self-replicating materials in prebiotic C.; Napolitano, E.; Musumeci, D.; Roviello, G.N. From Prebiotic chemistry, as well as their application as constituents of innovative drug delivery systems and, more Chemistry to Supramolecular generally, as novel nanomaterials to be employed in biomedicine.
    [Show full text]
  • Synthesis of Different Types of Pnas, Containing Chiral Pseudopeptide Backbone
    Trakia Journal of Sciences, Vol. 8, Suppl. 2, pp 98-101, 2010 Copyright © 2009 Trakia University Available online at: http://www.uni-sz.bg ISSN 1313-7050 (print) ISSN 1313-3551 (online) SYNTHESIS OF DIFFERENT TYPES OF PNAS, CONTAINING CHIRAL PSEUDOPEPTIDE BACKBONE T. Dzimbova*, T. Pajpanova Institute of Molecular Biology, BAS, Sofia, Bulgaria ABSTRACT Peptide nucleic acid (PNA) is a nucleic acid analogues with an achiral polyamide backbone consisting of N-(2-aminoethyl)glycine units. The purine or pyrimidine bases are linked to the each unit via a methylene carbonyl linker to target the complementary nucleic acid. Chiral PNAs were found to form slightly less stable PNA–DNA duplexes than their achiral analogues. By introducing positively charged Lys based monomers, more stable PNA–DNA duplexes were obtained. In this work we presented synthesis for several new PNAs, containing chiral pseudopeptide backbone. Key words: unnatural amino acids, nucleic acid analogs, arginine, canavanine INTRODUCTION specific DNA/RNA binding agents. Many In 1991 Nielson, Egholm, Berg and Buchardt second-generation PNA-like molecules have (1, 2) reported the synthesis of peptide nucleic been designed, synthesized and evaluated for acids (PNAs), a new completely artificial interesting or improved properties. For DNA/RNA analogues in which the backbone is example, much work has been devoted to a pseudopeptide rather than a sugar. First investigate various cyclic backbone-based PNAs were based upon an N-(2- PNAs, with the goal of increasing the aminoethyl)glycine pseudopeptide backbone. selectivity or strength of interaction with The bases (corresponding to A, G, C, T) are natural nucleic acids. Another class of PNA attached to the backbone via a methylene analogues is based on a diamino acid backbone carbonyl linker.
    [Show full text]