Contryphan Genes and Mature Peptides in the Venom of Nine Cone Snail Species by Transcriptomic and Mass Spectrometric Analysis

Vijayasarathy, Marimuthu; Basheer, Soorej M.; Franklin, Jayaseelan Benjamin; Balaram, Padmanabhan

doi:10.1021/acs.jproteome.6b00776

Cited by 17 publications

(9 citation statements)

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“…Mass spectrometry based identification of single-disulfide peptides -The presence of contryphans in the venom of cone snails from India have been reported earlier (9,(21)(22)(23). In this study, a focused search for other classes of single-disulfide peptides of novel sequences in the venoms of cone snails found in the Indian coastal waters was carried out by mass spectrometric analysis of the crude venom components.…”

Section: Resultsmentioning

confidence: 93%

Structure and allosteric activity of a single-disulfide conopeptide from Conus zonatus at human α3β4 and α7 nicotinic acetylcholine receptors

Mohan

Abraham

Rajesh

et al. 2020

Journal of Biological Chemistry

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Conopeptides are neurotoxic peptides in the venom of marine cone snails and have broad therapeutic potential for managing pain and other conditions. Here, we identified the single-disulfide peptides Czon1107 and Cca1669 from the venoms of Conus zonatus and Conus caracteristicus, respectively. We observed that Czon1107 strongly inhibits the human α3β4 (IC50 15.7 ± 3.0 μm) and α7 (IC50 77.1 ± 0.05 μm) nicotinic acetylcholine receptor (nAChR) subtypes, but the activity of Cca1669 remains to be identified. Czon1107 acted at a site distinct from the orthosteric receptor site. Solution NMR experiments revealed that Czon1107 exists in equilibrium between conformational states that are the result of a key Ser4–Pro5cis-trans isomerization. Moreover, we found that the X-Pro amide bonds in the inter-cysteine loop are rigidly constrained to cis conformations. Structure-activity experiments of Czon1107 and its variants at positions P5 and P7 revealed that the conformation around the X-Pro bonds (cis-trans) plays an important role in receptor subtype selectivity. The cis conformation at the Cys6–Pro7 peptide bond was essential for α3β4 nAChR subtype allosteric selectivity. In summary, we have identified a unique single-disulfide conopeptide with a noncompetitive, potentially allosteric inhibitory mechanism at the nAChRs. The small size and rigidity of the Czon1107 peptide could provide a scaffold for rational drug design strategies for allosteric nAChR modulation. This new paradigm in the “conotoxinomic” structure-function space provides an impetus to screen venom from other Conus species for similar, short bioactive peptides that allosterically modulate ligand-gated receptor function.

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Section: Resultsmentioning

confidence: 93%

Structure and allosteric activity of a single-disulfide conopeptide from Conus zonatus at human α3β4 and α7 nicotinic acetylcholine receptors

Mohan

Abraham

Rajesh

et al. 2020

Journal of Biological Chemistry

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“…Analysis of Li504 and Li520 Precursor peptide sequences. The sequences were deduced by the nextgeneration sequencing method as described by Sarathy et al 26 from the venom duct of C. lividus. The precursor peptides were subjected to BLAST in Pubmed (https://blast.ncbi.nlm.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

“…In the ongoing project of deep sequencing of venom duct transcriptome of Indian marine cone snails, − a novel peptide homologous to the active site motif of PDI and csPDI was deduced from Conus lividus . Analysis of precursor sequences in the databases has revealed the presence of a similar disulfide motif with an extension of N-terminal sequence in conopeptides derived from Conus ermineus , Conus marmoreus , and Conus victoriae.…”

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confidence: 99%

The Redox-Active Conopeptide Derived from the Venom Duct Transcriptome of Conus lividus Assists in the Oxidative Folding of Conotoxin

et al. 2021

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The tetrapeptides Li504 and Li520, differing in the modification of the 4trans-hydroxylation of proline, are novel conopeptides derived from the venom duct transcriptome of the marine cone snail Conus lividus. These predicted mature peptides are homologous to the active site motif of oxidoreductases that catalyze the oxidation, reduction, and rearrangement of disulfide bonds in peptides and proteins. The estimated reduction potential of the disulfide of Li504 and Li520 is within the range of disulfide reduction potentials of oxidoreductases, indicating that they may catalyze the oxidative folding of conotoxins. Conformational features of Li504 and Li520 include the trans configuration of the Cys1−Pro2/Hyp2 peptide bond with a type 1 turn that is similar to the active site motif of glutaredoxin that regulates the oxidation of cysteine thiols to disulfides. Li504-and Li520-assisted oxidative folding of α-conotoxin ImI confirms that Li520 improves the yield of the natively folded peptide by concomitantly decreasing the yield of the non-native disulfide isomer and thus acts as a miniature disulfide isomerase. The geometry of the Cys1−Hyp2 peptide bond of Li520 shifts between the trans and cis configurations in the disulfide form and thiol/thiolate form, which regulates the deprotonation of the N-terminal cysteine residue. Hydrogen bonding of the hydroxyl group of 4-trans-hydroxyproline with the interpeptide chain unit in the mixed disulfide form may play a vital role in shifting the geometry of the Cys1−Hyp2 peptide bond from cis to trans configuration. The Li520 conopeptide together with similar peptides derived from other species may constitute a new family of "redox-active" conopeptides that are integral components of the oxidative folding machinery of conotoxins.

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“…Nine cone snail species, C. amadis , C. loroisii, C. monile , C. araneosus, C. lividus , C. ebraeus , C. frigidus , C. miles , and C. litteratus , which are not listed as endangered taxa, were examined in this study. The procedures for sample collection, venom duct dissection, RNA extraction, and NGS assembly have been previously described . Putative protein sequences obtained in all six open reading frames were collected into single data sets for each species to facilitate further mining.…”

Section: Methodsmentioning

confidence: 99%

“…Global reduction of disulfide bonds and alkylation of free thiol groups was carried out using tris (2-carboxyethyl)-phosphine (TCEP)/ N -ethyl maleimide(NEM) using previously described procedures. , …”

Section: Methodsmentioning

confidence: 99%

Cone Snail Glutaminyl Cyclase Sequences from Transcriptomic Analysis and Mass Spectrometric Characterization of Two Pyroglutamyl Conotoxins

2018

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The post-translational modification of N-terminal glutamine (Q) to a pyroglutamyl (Z) residue is observed in the conotoxins produced by marine cone snails. This conversion requires the action of the enzyme glutaminyl cyclase (QC). Four complete QC sequences from the species C. araneosus, C. frigidus, C. litteratus, and C. monile and two partial sequences from C. amadis and C. miles have been obtained by analysis of transcriptomic data. Comparisons with mammalian enzyme sequences establish a high level of identity and complete conservation of functional active site residues, including a cluster of hydrogen-bonded acidic side chains. Mass spectrometric analysis of crude venom samples coupled to conotoxin precursor protein sequences obtained from transcriptomic data establishes the presence of pyroglutamyl conotoxins in the venom of C. frigidus and C. amadis. The C. frigidus peptide belongs to the M superfamily, with cysteine framework III, whereas the C. amadis peptide belongs to the divergent superfamily with cysteine framework VI/VII. Additionally, gamma carboxylation of glutamic acid and hydroxylation of proline are observed in the C. frigidus peptide. Mass spectral data are available via ProteomeXchange with identifier PXD009006.

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Contryphan Genes and Mature Peptides in the Venom of Nine Cone Snail Species by Transcriptomic and Mass Spectrometric Analysis

Cited by 17 publications

References 50 publications

Structure and allosteric activity of a single-disulfide conopeptide from Conus zonatus at human α3β4 and α7 nicotinic acetylcholine receptors

Structure and allosteric activity of a single-disulfide conopeptide from Conus zonatus at human α3β4 and α7 nicotinic acetylcholine receptors

The Redox-Active Conopeptide Derived from the Venom Duct Transcriptome of Conus lividus Assists in the Oxidative Folding of Conotoxin

Cone Snail Glutaminyl Cyclase Sequences from Transcriptomic Analysis and Mass Spectrometric Characterization of Two Pyroglutamyl Conotoxins

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