Ligand-induced conformational change in the minimized insulin receptor.

Autor: Schlein M; Health Care Discovery, Novo Nordisk A/S, Novo Alle 1, DK 2880, Bagsvaerd, Denmark., Havelund S, Kristensen C, Dunn MF, Kaarsholm NC
Jazyk: angličtina
Zdroj: Journal of molecular biology [J Mol Biol] 2000 Oct 20; Vol. 303 (2), pp. 161-9.
DOI: 10.1006/jmbi.2000.4134
Abstrakt: Within the class of insulin and insulin-like growth factor receptors, detailed information about the molecular recognition event at the hormone-receptor interface is limited by the absence of suitable co-crystals. We describe the use of a biologically active insulin derivative labeled with the NBD fluorophore (B29NBD-insulin) to characterize the mechanism of reversible 1:1 complex formation with a fragment of the insulin receptor ectodomain. The accompanying 40 % increase in the fluorescence quantum yield of the label provides the basis for a dynamic study of the hormone-receptor binding event. Stopped-flow fluorescence experiments show that the kinetics of complex formation are biphasic comprising a bimolecular binding event followed by a conformational change. Displacement with excess unlabeled insulin gave monophasic kinetics of dissociation. The rate data are rationalized in terms of available experiments on mutant receptors and the X-ray structure of a non-binding fragment of the receptor of the homologous insulin-like growth factor (IGF-1).
(Copyright 2000 Academic Press.)
Databáze: MEDLINE
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