1l5c
Solution Structure of the Monomeric Form of a Mutant Unliganded Bovine Neurophysin, 20 Structures
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OverviewOverview
Determination of the structure of the unliganded monomeric state of, neurophysin is central to an understanding of the allosteric relationship, between neurophysin peptide-binding and dimerization. We examined this, state by NMR, using the weakly dimerizing H80E mutant of bovine, neurophysin-I. The derived structure, to which more than one conformer, appeared to contribute, was compared with the crystal structure of the, unliganded des 1-6 bovine neurophysin-II dimer. Significant conformational, differences between the two proteins were evident in the orientation of, the 3,10 helix, in the 50-58 loop, in beta-turns, and in specific, intrachain contacts between amino- and carboxyl domains. However, both had, similar secondary structures, in independent confirmation of earlier, circular dichroism studies. Previously suggested interactions between the, amino terminus and the 50-58 loop in the monomer were also confirmed., Comparison of the observed differences between the two proteins with, demonstrated effects of dimerization on the NMR spectrum of bovine, neurophysin-I, and preliminary investigation of the effects of, dimerization on H80E spectra, allowed tentative distinction between the, contributions of sequence and self-association differences to the, difference in conformation. Regions altered by dimerization encompass most, binding site residues, providing a potential explanation of differences in, binding affinity between the unliganded monomeric and dimeric states., Differences between monomer and dimer states in turns, interdomain, contacts, and within the interdomain segment of the 50-58 loop suggest, that the effects of dimerization on intrasubunit conformation reflect the, need to adjust the relative positions of the interface segments of the two, domains for optimal interaction with the adjacent subunit and/or reflect, the dual role of some residues as participants both at the interface and, in interdomain contacts.
About this StructureAbout this Structure
1L5C is a Single protein structure of sequence from Bos taurus. Full crystallographic information is available from OCA.
ReferenceReference
NMR analysis of the monomeric form of a mutant unliganded bovine neurophysin: comparison with the crystal structure of a neurophysin dimer., Nguyen TL, Breslow E, Biochemistry. 2002 May 7;41(18):5920-30. PMID:11980496
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