ISOLATION AND CHARACTERIZATION OF NOVEL CONOPEPTIDES FROM THE MARINE CONE SNAIL: CONUS BRUNNEUS by Fred C. Pflueger A Dissertation Submitted to the Faculty of The Charles E. Schmidt College of Science in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy Florida Atlantic University Boca Raton, Fl December 2008 ACKNOWLEDGEMENTS I would like to thank Dr. Frank Mari for his friendship, time, and for giving me the opportunity to conduct research under his guidance. I would also like to thank Dr. Gregg Fields, Dr. Gary Perry, and Dr. Andrew Terentis for their time, help, advice, and efforts as members of my dissertation committee. Most importantly I would like to thank Jacqueline, my wife, friend, and good mother to our children; Fred, my father, mentor, and the man who gave me the world; and Claudia, my mother for her unconditional love and support. This dissertation is dedicated to my children, Alexandria and Frederick, for giving me the strength and determination to finish this work. iii ABSTRACT Author: Fred C. Pflueger Title: Isolation and Characterization of Novel Conopeptides from the Marine Cone Snail: Conus brunneus Institution: Florida Atlantic University Dissertation Advisor: Dr. Frank Mari Degree: Doctor of Philosophy Year: 2008 Cone snails are predatory marine gastropods that use venom for means of predation and defense. This venom is a complex mixture of conopeptides that selectivity binds to ion channels and receptors, giving them a wide range of potential pharmaceutical applications. Conus brunneus is a wide spread Eastern Pacific cone snail species that preys upon worms (vermivorous). Vermivorous cone snails have developed very specific biochemical strategies for the immobilization of their prey and there venom has not been extensively studied to date. The main objective of this dissertation is the characterization of novel conopeptides isolated from Conus brunneus. Chapter 1 is an introduction and background on cone snails and conopeptides. Chapter 2 details the isolation and characterization of a novel P-superfamily conotoxin. Chapter 3 presents the 3D solution structure of the novel P-superfamily conotoxin. Chapter 4 details the isolation and iv characterization of two novel M-superfamily conotoxins. Chapter 5 covers the use of nano-NMR to characterize a novel P-superfamily conotoxin using nanomole quantities of sample. Chapter 6 is a reprint of a paper published in the Journal of the American Chemical Society in which we combined and implemented techniques developed in the previous chapters to report the presence of D-γ-Hydroxyvaline in a polypeptide chain. This dissertation contains the first reported work of a P-superfamily structure obtained directly from the crude venom therefore accurately representing native post-translational modifications. In this paper, crude cone snail venom was characterized by: high performance liquid chromatography, nuclear magnetic resonance spectroscopy, nano- nuclear magnetic resonance spectroscopy, mass spectrometry, amino acid analysis, Edman degradation sequencing, and preliminary bioassays. v TABLE OF CONTENTS LIST OF FIGURES………………………………………………………….…………..xi LIST OF TABLES………………………………………………………………..…...…xv CHAPTER 1 .......................................................................................................................1 Background and Introduction ............................................................................................. 1 Neurotoxins .....................................................................................................................3 Conopeptides................................................................................................................... 3 Post-translational modifications...................................................................................... 7 Anatomy of the Cone Snail ............................................................................................. 7 Anatomy of the Venom Apparatus.................................................................................. 9 Conus brunneus............................................................................................................. 11 Conus gladiator............................................................................................................. 19 Summary ....................................................................................................................... 20 REFERENCES.............................................................................................................. 21 CHAPTER 2 ..................................................................................................................... 25 Conotoxin bru9a, a Novel P-Superfamily Conopeptide from the Venom of Conus brunneus. Isolation and Characterization. ........................................................................ 25 ABSTRACT.................................................................................................................. 25 INTRODUCTION......................................................................................................... 25 MATERIALS AND METHODS.................................................................................. 27 Specimen Collection.................................................................................................. 27 Venom Duct Removal ............................................................................................... 28 vi Extraction of Crude Venom....................................................................................... 29 Purification of Peptides ............................................................................................. 31 Mass Spectrometry .................................................................................................... 32 Reduction and Alkylation.......................................................................................... 33 Partial Reduction and Alkylation .............................................................................. 33 Promotion and Stabilization of b1 peptide using N-terminal derivatives. ................. 33 Amino Acid Analysis ................................................................................................ 34 NMR Spectroscopy ................................................................................................... 34 Peptide Sequencing.................................................................................................... 34 Bioassays ................................................................................................................... 35 Nomenclature............................................................................................................. 35 RESULTS AND DISCUSSION ................................................................................... 36 Purification of Peptides ............................................................................................. 36 Mass Spectrometry .................................................................................................... 43 Reduction and Alkylation.......................................................................................... 44 Partial Reduction and Alkylation .............................................................................. 48 Promotion and Stabilization of B1 peptide using N-terminal derivatives................. 49 Peptide Amino Acid Analysis ................................................................................... 53 Peptide Sequencing.................................................................................................... 54 Bioassays ................................................................................................................... 54 REFERENCES.............................................................................................................. 56 CHAPTER 3 ..................................................................................................................... 58 Three–Dimensional Solution Structure of Conotoxin bru9a: a Novel P-Superfamily Conotoxin from the Venom of Conus brunneus with an Unusual Cystine Knot Motif. .. 58 ABSTRACT.................................................................................................................. 58 vii INTRODUCTION......................................................................................................... 58 MATERIALS AND METHODS.................................................................................. 61 Preparation of bru9a .................................................................................................. 61 NMR Sample Preparation.......................................................................................... 61 NMR Spectroscopy ................................................................................................... 62 Structural Assignments and Restraints...................................................................... 62 Structure Calculations................................................................................................ 64 RESULTS AND DISCUSSION ................................................................................... 64 Structural Assignments.............................................................................................. 64 Secondary Structure..................................................................................................