1wme: Difference between revisions

[[Image:1wme.gif|left|200px]]<br /><applet load="1wme" size="350" color="white" frame="true" align="right" spinBox="true"  

The 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.

1WME is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacteria Bacteria] with <scene name='pdbligand=CA:'>CA</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1WME OCA].  

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