Molecular dynamics study of major urinary protein-pheromone interactions: A structural model for ligand-induced flexibility increase
Pavel Macek1, Petr Novák1, Lukáš Žídek1 and Vladimír Sklenář1
1National Centre for Biomolecular Research, Faculty of Science, Masaryk University, Kamenice 5/A4, Brno, 611 37, Czech Republic
Recently, two independent 15N NMR relaxation studies [1,2] indicated that in contrast to the decreased flexibility expected for induced-fit interactions, the backbone flexibility of major urinary protein isoform I (MUP-I) slightly increased upon complex formation with its natural pheromone 2-sec-butyl-4,5-dihydrothiazol. We have analyzed motions in terms of frequency-dependent and conformation-dependent order parameters S2 by molecular dynamics simulations of free- and complexed protein. In general, calculated order parameters S2 agree with the NMR relaxation data. Structural analysis supplied evidence that mobility in different regions can be attributed to small conformational changes of free- and complexed protein, which results from hydrogen bonding network modifications .
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