title: I-superfamily conotoxins: sequence and structure analysis.
abstract: I-superfamily conotoxins have four-disulfide bonds with cysteine arrangement C-C-CC-CC-C-C, and they inhibit or modify ion channels of nerve cells. They have been characterized only recently and are relatively less well studied compared to other superfamily conotoxins. We have detected selective and sensitive sequence pattern for I-superfamily conotoxins. The availability of sequence pattern should be useful in protein family classification and functional annotation. We have built by homology modeling, a theoretical structural 3D model of ViTx from Conus virgo, a typical member of I-superfamily conotoxins. The modeling was based on the available 3D structure of Janus-atracotoxin-Hv1c of Janus-atracotoxin family whose members have been suggested as possible biopesticides. A study comparing the theoretically modeled structure of ViTx, with experimentally determined structures of other toxins, which share functional similarity with ViTx, reveals the crucial role of C-terminal region of ViTx in blocking therapeutically important voltage-gated potassium channels.
authors.affiliation: Department of Physics, Indian Institute of Science, Bangalore 560 012, India.
authors.forename: Sukanta
authors.initials: S
authors.lastname: Mondal
authors.forename: Ramachandran
authors.initials: R
authors.lastname: Vijayan
authors.forename: Kannambath
authors.initials: K
authors.lastname: Shichina
authors.forename: Rajasekaran Mohan
authors.initials: RM
authors.lastname: Babu
authors.forename: Suryanarayanarao
authors.initials: S
authors.lastname: Ramakumar
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D019295:Computational Biology; D003198:Computer Simulation; D020916:Conotoxins / Q000737:chemistry* / Q000145:classification / Q000235:genetics*; D017124:Conserved Sequence; D052078:Conus Snail / Q000235:genetics; D003545:Cysteine / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D055672:Static Electricity
chemical_list: D000596:Amino Acids; D020916:Conotoxins; D003545:Cysteine