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Crystal Structure of alkaline serine protease KP-43 from Bacillus sp. KSM-KP43 (oxidized form, 1.73 angstrom)
Structural highlights
FunctionEvolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe crystal structure of an oxidatively stable subtilisin-like alkaline serine protease, KP-43 from Bacillus sp. KSM-KP43, with a C-terminal extension domain, was determined by the multiple isomorphous replacements method with anomalous scattering. The native form was refined to a crystallographic R factor of 0.134 (Rfree of 0.169) at 1.30-A resolution. KP-43 consists of two domains, a subtilisin-like alpha/beta domain and a C-terminal jelly roll beta-barrel domain. The topological architecture of the molecule is similar to that of kexin and furin, which belong to the subtilisin-like proprotein convertases, whereas the amino acid sequence and the binding orientation of the C-terminal beta-barrel domain both differ in each case. Since the C-terminal domains of subtilisin-like proprotein convertases are essential for folding themselves, the domain of KP-43 is also thought to play such a role. KP-43 is known to be an oxidation-resistant protease among the general subtilisin-like proteases. To investigate how KP-43 resists oxidizing reagents, the structure of oxidized KP-43 was also determined and refined to a crystallographic R factor of 0.142 (Rfree of 0.212) at 1.73-A resolution. The structure analysis revealed that Met-256, adjacent to catalytic Ser-255, was oxidized similarly to an equivalent residue in subtilisin BPN'. Although KP-43, as well as proteinase K and subtilisin Carlsberg, lose their hydrolyzing activity against synthetic peptides after oxidation treatment, all of them retain 70-80% activity against proteinaceous substrates. These results, as well as the beta-casein digestion pattern analysis, have indicated that the oxidation of the methionine adjacent to the catalytic serine is not a dominant modification but might alter the substrate specificities. The crystal structure of an oxidatively stable subtilisin-like alkaline serine protease, KP-43, with a C-terminal beta-barrel domain.,Nonaka T, Fujihashi M, Kita A, Saeki K, Ito S, Horikoshi K, Miki K J Biol Chem. 2004 Nov 5;279(45):47344-51. Epub 2004 Sep 1. PMID:15342641[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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