1m24
Trichotoxin_A50E, An Ion Channel-Forming PolypeptideTrichotoxin_A50E, An Ion Channel-Forming Polypeptide
Structural highlights
Publication Abstract from PubMedTrichotoxin_A50E is an 18-residue peptaibol antibiotic which forms multimeric transmembrane channels through self-association. The crystal structure of trichotoxin has been determined at a resolution of 0.9 A. The trichotoxin sequence contains nine helix-promoting Aib residues, which contribute to the formation of an entirely helical structure that has a central bend of 8-10 degrees located between residues 10-13. Trichotoxin is the first solved structure of the peptaibol family that is all alpha-helix as opposed to containing part or all 3(10)-helix. Gln residues in positions 6 and 17 produce a polar face, and are proposed to form the channel lumen. An octameric model channel has been constructed from the crystal structure. It has a central pore of approximately 4-5 A radius, a size sufficient to enable transport of ions, with a constricted region at one end, formed by a ring of Gln6 residues. Electrostatic calculations are consistent with it being a cationic channel. Model for a helical bundle channel based on the high-resolution crystal structure of trichotoxin_A50E.,Chugh JK, Bruckner H, Wallace BA Biochemistry. 2002 Oct 29;41(43):12934-41. PMID:12390019[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References |
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