1ah2
SERINE PROTEASE PB92 FROM BACILLUS ALCALOPHILUS, NMR, 18 STRUCTURES
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OverviewOverview
BACKGROUND: Research on high-alkaline proteases, such as serine protease, PB92, has been largely inspired by their industrial application as, protein-degrading components of washing powders. Serine protease PB92 is a, member of the subtilase family of enzymes, which has been extensively, studied. These studies have included exhaustive protein engineering, investigations and X-ray crystallography, in order to provide insight into, the mechanism and specificity of enzyme catalysis. Distortions have been, observed in the substrate-binding region of subtilisin crystal structures, due to crystal contacts. In addition, the structural variability in the, substrate-binding region of subtilisins is often attributed to, flexibility. It was hoped that the solution structure of this enzyme would, provide further details about the conformation of this key region and give, new insights into the functional properties of these enzymes. RESULTS: The, three-dimensional solution structure of the 269-residue (27 kDa) serine, protease PB92 has been determined using distance and dihedral angle, constraints derived from triple-resonance NMR data. The solution structure, is represented by a family of 18 conformers which overlay onto the average, structure with backbone and all-heavy-atom root mean square deviations, (for the main body of the molecule) of 0.88 and 1.21 A, respectively. The, family of structures contains a number of regions of relatively high, conformational heterogeneity, including various segments that are involved, in the formation of the substrate-binding site. The presence of, flexibility within these segments has been established from NMR relaxation, parameters and measurements of amide proton exchange rates. CONCLUSIONS:, The solution structure of the serine protease PB92 presents a well defined, global fold which is rigid with the exception of a restricted number of, sites. Among the limited number of residues involved in significant, internal mobility are those of two pockets, termed S1 and S4, within the, substrate-binding site. The presence of flexibility within the binding, site supports the proposed induced fit mechanism of substrate binding.
About this StructureAbout this Structure
1AH2 is a Single protein structure of sequence from Bacillus alcalophilus. Known structural/functional Site: . Full crystallographic information is available from OCA.
ReferenceReference
The solution structure of serine protease PB92 from Bacillus alcalophilus presents a rigid fold with a flexible substrate-binding site., Martin JR, Mulder FA, Karimi-Nejad Y, van der Zwan J, Mariani M, Schipper D, Boelens R, Structure. 1997 Apr 15;5(4):521-32. PMID:9115441
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