1uhg
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Crystal Structure of S-Ovalbumin At 1.9 Angstrom Resolution
OverviewOverview
Ovalbumin, a non-inhibitory member of serine proteinase inhibitors, (serpin), is transformed into a heat-stabilized form, S-ovalbumin, under, elevated pH conditions. The structural mechanism for the S-ovalbumin, formation has long been a puzzling question in food science and serpin, structural biology. On the basis of the commonly observed serpin, thermostabilization by insertion of the reactive center loop into the, proximal beta-sheet, the most widely accepted hypothetical model has, included partial loop insertion. Here we demonstrate, for the first time, the crystal structure of S-ovalbumin at 1.9-A resolution. This structure, unequivocally excludes the partial loop insertion mechanism; the overall, structure, including the reactive center loop structure, is almost the, same as that of native ovalbumin, except for the significant motion of the, preceding loop of strand 1A away from strand 2A. The most striking finding, is that Ser-164, Ser-236, and Ser-320 take the d-amino acid residue, configuration. These chemical inversions can be directly related to the, irreversible and stepwise nature of the transformation from native, ovalbumin to S-ovalbumin. As conformational changes of the side chains, significant alternations are found in the values of the chi 1 of Phe-99, and the chi 3 of Met-241. The former conformational change leads to the, decreased solvent accessibility of the hydrophobic core around Phe-99, which includes Phe-180 and Phe-378, the highly conserved residues in, serpin. This may give a thermodynamic advantage to the structural, stability of S-ovalbumin.
About this StructureAbout this Structure
1UHG is a Single protein structure of sequence from Gallus gallus with NAG and SO4 as ligands. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of S-ovalbumin as a non-loop-inserted thermostabilized serpin form., Yamasaki M, Takahashi N, Hirose M, J Biol Chem. 2003 Sep 12;278(37):35524-30. Epub 2003 Jul 1. PMID:12840013
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