Ikematsu M, Takaoka D, Yasuda M. Odorant binding initially occurring at the central pocket in bovine odorant-binding protein.
Biochem Biophys Res Commun 2005;
333:1227-33. [PMID:
15979570 DOI:
10.1016/j.bbrc.2005.06.031]
[Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2005] [Accepted: 06/07/2005] [Indexed: 10/25/2022]
Abstract
Why bovine odorant-binding protein (OBPb), among OBP family, assumes a dimeric structure has been unclear. Here we clarified, by measuring the fluorescence of intrinsic tryptophan and tyrosine residues of intact OBPb and OBPb whose C-terminal 10 amino acids were deleted, that odorant enters the central pocket formed by the dimerization when OBPb first encounters odorant, and odorant with high affinity with OBPb subsequently enters the internal cavity (suggested binding site), releasing the pre-bound odorant. The internal cavity-bound odorant can be released by the binding of other odorants at another internal cavity or at the central pocket, depending on the binding odorants. Due to this mechanism enabled by the dimerization, OBPb is more reactive than other monomeric OBPs.
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