title: Proteinase inhibitor homologues as potassium channel blockers.
abstract: We report here the NMR structure of dendrotoxin I, a powerful potassium channel blocker from the venom of the African Elapidae snake Dendroaspis polylepis polylepis (black mamba), calculated from an experimentally-derived set of 719 geometric restraints. The backbone of the toxin superimposes on bovine pancreatic trypsin inhibitor (BPTI) with a root-mean-square deviation of < 1.7 A. The surface electrostatic potential calculated for dendrotoxin I and BPTI, reveal an important difference which might account for the differences in function of the two proteins. These proteins may provide examples of adaptation for specific and diverse biological functions while at the same time maintaining the overall three-dimensional structure of a common ancestor.
authors.affiliation: Institute de Biologie Structurale CEA-CNRS, Grenoble, France.
authors.forename: J M
authors.initials: JM
authors.lastname: Lancelin
authors.forename: M F
authors.initials: MF
authors.lastname: Foray
authors.forename: M
authors.initials: M
authors.lastname: Poncin
authors.forename: M
authors.initials: M
authors.lastname: Hollecker
authors.forename: D
authors.initials: D
authors.lastname: Marion
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D007611:Aprotinin / Q000737:chemistry / Q000235:genetics; D005075:Biological Evolution; D002417:Cattle; D004546:Elapid Venoms / Q000737:chemistry* / Q000235:genetics / Q000494:pharmacology*; D017815:Elapidae; D004563:Electrochemistry; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D026902:Potassium Channel Blockers; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
chemical_list: D004546:Elapid Venoms; D026902:Potassium Channel Blockers; C020273:dendrotoxin; D007611:Aprotinin