1esp
From Proteopedia
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NEUTRAL PROTEASE MUTANT E144S
Overview
The X-ray crystal structure of the Bacillus cereus neutral protease (CNP), active-site mutant E144S, in which the putative general base proposed for, the thermolysin-like zinc neutral proteases, Glu144, has been replaced by, serine, has been determined to a resolution of 2.8 A. This represents the, first crystal structure of an active-site mutant of a zinc neutral, protease. The E 144S mutant was crystallized in the hexagonal space group, P6(5)22, with unit-cell dimensions a = b = 76.57, c = 201.91 A. Although, the ligands involved in zinc coordination in the active site are identical, to those found in the wild-type protein, the mutation results in a, modified environment around the zinc ion; particularly with respect to the, water molecules. While the structure of the mutant is similar to that of, wild type, its protease activity is reduced to 0.16% that of the wild-type, CNP and the protein is virtually resistant to autolysis in the presence of, calcium. The lowered protease activity of the mutant is consistent with, the role proposed for Glu144 as the general base in the catalysis of, thermolysin-like neutral proteases [Matthews (1988). Acc. Chem. Res. 21, 333-340]. We suggest that the residual activity of the E144S mutant arises, from a water molecule, which is found within hydrogen-bonding distance of, Ser144, acting as a general base in the catalytic function of the mutant.
About this Structure
1ESP is a Single protein structure of sequence from Bacillus cereus with CA and ZN as ligands. Full crystallographic information is available from OCA.
Reference
E144S active-site mutant of the Bacillus cereus thermolysin-like neutral protease at 2.8 A resolution., Lister SA, Wetmore DR, Roche RS, Codding PW, Acta Crystallogr D Biol Crystallogr. 1996 May 1;52(Pt 3):543-50. PMID:15299677
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