التفاصيل البيبلوغرافية
| العنوان: |
A diverse family of novel peptide toxins from an unusual cone snail, Conus callfornicus. |
| المؤلفون: |
Gilly, W. F., Richmond, T. A., Duda, Jr., T. F., EIIiger, C., Lebaric, Z., Schulz, J., Bingham, J. P., Sweedler, J. V. |
| المصدر: |
Journal of Experimental Biology; Jan2011, Vol. 214 Issue 1, p147-161, 15p |
| مصطلحات موضوعية: |
PEPTIDES, SPECIES diversity, MOLECULAR cloning, MASS spectrometry, MESSENGER RNA, GENE expression |
| مستخلص: |
Diversity among Conus toxins mirrors the high species diversity in the Indo-Pacific region, and evolution of both is thought to stem from feeding-niche specialization derived from intra-generic competition. This study focuses on Conus californicus, a phylogenetic outlier endemic to the temperate northeast Pacific. Essentially free of congeneric competitors, it preys on a wider variety of organisms than any other cone snail. Using molecular cloning of cDNAs and mass spectrometry, we examined peptides isolated from venom ducts to elucidate the sequences and post-translational modifications of two eight-cysteine toxins (caIl2a and call2b of type 12 framework) that block voltage-gated Na2 channels. Based on homology of leader sequence and mode of action, these toxins are related to the O-superfamily, but differ significantly from other members of that group. Six of the eight cysteine residues constitute the canonical framework of O-members, but two additional cysteine residues in the N-terminal region define an O+2 classification within the O-superfamily. Fifteen putative variants of Ca112.1 toxins have been identified by mRNAs that differ primarily in two short hypervariable regions and have been grouped into three subtypes (Ca112.1.1-3). This unique modular variation has not been described for other Conus toxins and suggests recombination as a diversity-generating mechanism. We propose that these toxin isoforms show specificity for similar molecular targets (Na+ channels) in the many species preyed on by C. californicus and that individualistic utilization of specific toxin isoforms may involve control of gene expression. [ABSTRACT FROM AUTHOR] |
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| قاعدة البيانات: |
Complementary Index |
