1lir
From Proteopedia
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LQ2 FROM LEIURUS QUINQUESTRIATUS, NMR, 22 STRUCTURES
Overview
Lq2 is a unique scorpion toxin. Acting from the extracellular side, Lq2, blocks the ion conduction pore in not only the voltage- and Ca2+, -activated channels, but also the inward-rectifier K+ channels. This, finding argues that the three-dimensional structures of the pores in these, K+ channels are similar. However, the amino acid sequences that form the, external part of the pore are minimally conserved among the various, classes of K+ channels. Because Lq2 can bind to all the three classes of, K+ channels, we can use Lq2 as a structural probe to examine how the, non-conserved pore-forming sequences are arranged in space to form similar, pore structures. In the present study, we determined the three-dimensional, structure of Lq2 using nuclear magnetic resonance (NMR) techniques. Lq2, consists of an alpha-helix (residues S10 to L20) and a beta-sheet, connected by an alphabeta3 loop (residues N22 to N24). The beta-sheet has, two well-defined anti-parallel strands (residues G26 to M29 and residues, K32 to C35), which are connected by a type I' beta-turn centered between, residues N30 and K31. The N-terminal segment (residues Z1 to T8) appears, to form a quasi-third strand of the beta-sheet.
About this Structure
1LIR is a Single protein structure of sequence from Leiurus quinquestriatus hebraeus. Full crystallographic information is available from OCA.
Reference
Solution structure of potassium channel-inhibiting scorpion toxin Lq2., Renisio JG, Lu Z, Blanc E, Jin W, Lewis JH, Bornet O, Darbon H, Proteins. 1999 Mar 1;34(4):417-26. PMID:10081954
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