2z2y
From Proteopedia
|
Crystal structure of autoprocessed form of Tk-subtilisin
Overview
Subtilisin from the hyperthermophilic archaeon Thermococcus kodakaraensis, (Tk-subtilisin) is matured from Pro-Tk-subtilisin upon autoprocessing and, degradation of the propeptide. The crystal structures of the autoprocessed, and mature forms of Tk-subtilisin were determined at 1.89 A and 1.70 A, resolution, respectively. Comparison of these structures with that of, unautoprocessed Pro-Tk-subtilisin indicates that the structure of, Tk-subtilisin is not seriously changed during maturation. However, one, unique Ca(2+)-binding site (Ca-7) is identified in these structures. In, addition, the N-terminal region of the mature domain (Gly70-Pro82), which, binds tightly to the main body in the unautoprocessed form, is disordered, and mostly truncated in the autoprocessed and mature forms, respectively., Interestingly, this site is formed also in the unautoprocessed form when, its crystals are soaked with 10 mM CaCl(2), as revealed by the 1.87 A, structure. Along with the formation of this site, the N-terminal region, (Leu75-Thr80) is disordered, with the scissile peptide bond contacting, with the active site. These results indicate that the calcium ion binds, weakly to the Ca-7 site in the unautoprocessed form, but is trapped upon, autoprocessing. We propose that the Ca-7 site is required to promote the, autoprocessing reaction by stabilizing the autoprocessed form, in which, the new N terminus of the mature domain is structurally disordered., Furthermore, the crystal structure of the Tk-propeptide:S324A-subtilisin, complex, which was formed by the addition of separately expressed, proteins, was determined at 1.65 A resolution. This structure is virtually, identical with that of the autoprocessed form, indicating that the, interaction between the two domains is highly intensive and specific.
About this Structure
2Z2Y is a Protein complex structure of sequences from Thermococcus kodakarensis with and as ligands. Active as Subtilisin, with EC number 3.4.21.62 Full crystallographic information is available from OCA.
Reference
Four new crystal structures of Tk-subtilisin in unautoprocessed, autoprocessed and mature forms: insight into structural changes during maturation., Tanaka S, Matsumura H, Koga Y, Takano K, Kanaya S, J Mol Biol. 2007 Sep 28;372(4):1055-69. Epub 2007 Jul 26. PMID:17706669
Page seeded by OCA on Wed Jan 23 11:53:54 2008
