Methionine acts as a “magnet” in photoaffinity crosslinking experiments
Abstract
Photoaffinity crosslinking has been utilized to probe the nature of the ligand–receptor interface for a number of G protein-coupled receptor systems. Often the photoreactive benzophenone moiety incorporated in the ligand is found to react with a methionine in the receptor. We introduced methionines one-at-a-time into the region 163–176 of the parathyroid hormone receptor, and find that crosslinking occurs to the side-chain of methionine over a range of 11 amino acids. We call this the “Magnet Effect” of methionine. Hence, crosslinking contact points can be significantly shifted by the presence of methionine in a receptor domain.
Abbreviations: Bpa, p-benzoylphenylalanine, Bpan-PTH, [Bpan,Nle8,18,Arg13,26,27,L-2-Nal23,Tyr34]bPTH(1–34)NH2, CNBr, cyanogen bromide, Endo-F, endoglycosidase F/N-glycosidase F, N-ECD, N-terminal extracellular domain, Nle, norleucine, PTH, parathyroid hormone, PTHR1, PTH receptor-1
Keywords: Parathyroid hormone receptor-1, Photoaffinity crosslinking, Cyanogen bromide, Methionine scan, Site-directed mutagenesis
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PII: S0014-5793(06)00251-1
doi:10.1016/j.febslet.2006.02.050
© 2006 Federation of European Biochemical Societies
