Definition of the M-conotoxin superfamily: characterization of novel peptides from molluscivorous Conus venoms.

摘要: Most of the >50 000 different pharmacologically active peptides in Conus venoms belong to a small number gene superfamilies. In this work, M-conotoxin superfamily is defined using both biochemical and molecular criteria. Novel excitatory purified from molluscivorous species textile marmoreusall have characteristic pattern Cys residues previously found I-, M-, a-conotoxins (CC-C-C-CC). The new are smaller (12- 19 amino acids) than (22-24 acids). One peptide, mr3a, was chemically synthesized biologically form. Analysis disulfide bridges natural peptide tx3c C. synthetic mr3a marmoreus showed novel connectivity, that established for I- a-conotoxins. Thus, these group structurally distinct conotoxins particularly prominent mollusc-hunting species. cDNA clones encoding as well those revealed highly conserved acid precursor sequences; conservation sequence defines superfamily, designated superfamily. characterized can be provisionally assigned four groups within M-superfamily based on similarity divergence between each group. A notable feature two structural frameworks been generated by changing connectivity an otherwise pattern.