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Isolation and characterization of neuroactive peptides from the venom of cone snail species
| Title: | Isolation and characterization of neuroactive peptides from the venom of cone snail species. |
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| Name(s): |
Cano, Herminsul Florida Atlantic University, Degree Grantor Mari, Frank, Thesis Advisor |
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| Type of Resource: | text | |
| Genre: | Electronic Thesis Or Dissertation | |
| Issuance: | monographic | |
| Date Issued: | 2005 | |
| Publisher: | Florida Atlantic University | |
| Place of Publication: | Boca Raton, Fla. | |
| Physical Form: | application/pdf | |
| Extent: | 169 p. | |
| Language(s): | English | |
| Summary: | The mam objective of the work described in this thesis is isolation and characterization of novel neuroactive peptides from the venom of cone snail species. The first section is an introduction about cone snails. The first chapter is dedicated to the analysis of the milked venom obtained from three different specimens of C. ermineus which is the only fish-hunter cone snail from the east Atlantic region. MALDI-TOF mass spectrometry analysis of two specimens showed an identical profile with all components of the venom being novel conopeptides. The third specimen showed a mass spectrometry profile with molecular weights corresponding to already reported conotoxins plus one additional new conopeptide. Ten new conotoxins were isolated from C. ermineus; seven of them have sequences corresponding to A-superfamily of conotoxins, specifically a-conotoxins family. Six of these seven conotoxins are the first a4/4 conotoxins isolated from the milked venom from any fish-hunter cone snail specimens; the other one is a a4/7 conotoxin similar sequence to the already reported a-EI from C. ermineus. Two more conotoxins that belong to the 0-superfamily have the same amino acid sequence with the only difference being a hydroxyproline residue instead of a proline at position 21 of the sequence. In the second chapter, four specimens of C. purpurascens, the only fish-hunter of the Eastern Pacific region were analyzed. One of the specimens was sacrified and the crude venom was dissected-out of the venom duct. For the three remaining live specimens the venom was obtained by the "milking" procedure. Mass spectrometry profiles were compared between dissected and milked venom and between milked venom from different specimens. Analysis showed both similarities and differences in the profiles of the dissected and the three milked venoms. A comparison of the three milked venoms found some differences. This analysis showed that one specimen expressed two isomorphs of a putative a4/4-conotoxin; the only difference was the presence of proline instead of hydroxyproline at position seven in the amino acid sequence. These a4/4-conotoxins are the second report of this sub-class of conotoxin from the milked venom of cone snails and they have sequence homology to the a4/4 conotoxins isolated from C. ermineus. The analysis of the MALDI-TOF MS/MS spectra of the Leu-contryphan-P conopeptide from C. purpurascens revealed that conotoxins with a single disulfide bond in the sequence behave as a linear peptide in the mass spectrometry experiment exhibiting a good fragmentation pattern. Using this information by comparing the MS/MS spectra we were able to identify L-contryphan-P conopeptide lacking the first Gly residue in the sequence. In the third chapter, three conotoxins with sequence homology to the omega-superfamily were isolated from the crude dissected venom of the worm-hunter cone snail C. vexillum. The precursor of one of these conotoxins was already characterized by another research group. Analysis and comparison of this precursor with already known precursor allowed us to hypothesize that these conotoxins were ro-conotoxins. Two of the three conotoxins have the same amino acid sequence with hydroxyproline instead a proline in the structure. These conotoxins were the first ones isolated from the venom duct of these cone snail species. Several conotoxins had been reported from C. vexillum but they were isolated using eDNA cloning techniques. Chapter four shows the analysis of the worm-hunter cone snail C. pseudoarantius crude venom. Eight novel conotoxins were isolated from the pooled duct dissected venom from different specimens. The first was a a4/3-conotoxin with a carboxyglutamate residue present at position one in the sequence. Five more conotoxins with conotoxin frameworks and sequences similar to M-superfamily of conotoxins were also found; additionally, two more novel conotoxins with sequence homology to o-conotoxins from the S-superfamily were isolated. All the above conotoxins were analyzed by comparison of their structures against sequences of known conotoxins. All 23 conotoxins found in this research are novel conopeptides isolated from cone snail specimens. Future work on the activity these conotoxins will be important in the search for possible drugs in treatment of many diseases. | |
| Identifier: | 9780542408748 (isbn), 12185 (digitool), FADT12185 (IID), fau:9092 (fedora) | |
| Note(s): | Thesis (Ph.D.)--Florida Atlantic University, 2005. | |
| Subject(s): |
Peptides--Structure Gastropoda--Venom Conus Mass spectrometry--Analysis |
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| Held by: | Florida Atlantic University Libraries | |
| Persistent Link to This Record: | http://purl.flvc.org/fcla/dt/12185 | |
| Sublocation: | Digital Library | |
| Use and Reproduction: | Copyright © is held by the author with permission granted to Florida Atlantic University to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder. | |
| Use and Reproduction: | http://rightsstatements.org/vocab/InC/1.0/ | |
| Host Institution: | FAU | |
| Is Part of Series: | Florida Atlantic University Digital Library Collections. |
