title: Molecular diversity and evolution of cystine knot toxins of the tarantula Chilobrachys jingzhao.
abstract: Cystine knot toxins (CKTs) in spider venoms represent a rich source of novel ligands for varied ion channels. Here, we identified 95 novel putative CKT precursors by analyzing expressed sequence tags of the tarantula Chilobrachys jingzhao venom gland. Phylogenetics analyses revealed one orphan family and six families with sequence similarity to known toxins. To further investigate the relationships of their structures, functions and evolution, we assayed 10 representative toxins for their effect on ion channels, and performed structure model comparisons, evolution analysis and toxin distribution analysis. This study revealed two major types of CKTs: pore-blocking toxins and gating modifier toxins. A few blockers were observed with relatively high abundance and wide distribution, which may be a category of original toxins that block channels conserved in various preys with relatively high specificity. The gating modifier families contain advanced toxins, usually have many members and interact with diverse regulatory components of channels.
authors.affiliation: The Key Laboratory of Protein Chemistry and Developmental Biology of Ministry of Education, College of Life Sciences, Hunan Normal University, Changsha, PR China.
authors.forename: J
authors.initials: J
authors.lastname: Chen
authors.forename: M
authors.initials: M
authors.lastname: Deng
authors.forename: Q
authors.initials: Q
authors.lastname: He
authors.forename: E
authors.initials: E
authors.lastname: Meng
authors.forename: L
authors.initials: L
authors.lastname: Jiang
authors.forename: Z
authors.initials: Z
authors.lastname: Liao
authors.forename: M
authors.initials: M
authors.lastname: Rong
authors.forename: S
authors.initials: S
authors.lastname: Liang
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D047168:Cystine Knot Motifs; D019143:Evolution, Molecular; D005727:Ganglia, Spinal / Q000187:drug effects / Q000378:metabolism; D014644:Genetic Variation; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D016415:Sequence Alignment; D013111:Spider Venoms / Q000737:chemistry* / Q000494:pharmacology; D013112:Spiders / Q000737:chemistry*; D040681:Structural Homology, Protein
chemical_list: D013111:Spider Venoms