1pj8
From Proteopedia
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'''Structure of a ternary complex of proteinase K, mercury and a substrate-analogue hexapeptide at 2.2 A resolution''' | '''Structure of a ternary complex of proteinase K, mercury and a substrate-analogue hexapeptide at 2.2 A resolution''' | ||
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[[Category: Visanji, M.]] | [[Category: Visanji, M.]] | ||
[[Category: Wilson, K S.]] | [[Category: Wilson, K S.]] | ||
| - | [[Category: | + | [[Category: Inhibitor]] |
| - | [[Category: | + | [[Category: Mercury]] |
| - | [[Category: | + | [[Category: Proteinase k]] |
| - | [[Category: | + | [[Category: Structure]] |
| - | [[Category: | + | [[Category: Ternary complex]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 05:08:36 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 02:08, 3 May 2008
Structure of a ternary complex of proteinase K, mercury and a substrate-analogue hexapeptide at 2.2 A resolution
Overview
The crystal structure of a ternary complex of proteinase K, Hg(II) and a hexapeptide N-Ac-Pro-Ala-Pro-Phe-Pro-Ala-NH2 has been determined at 2.2 A resolution and refined to an R factor of 0.172 for 12,910 reflections. The mercury atom occupies two alternate sites, each of which was assigned an occupancy of 0.45. These two sites are bridged by Cys-73 S gamma which forms covalent bonds to both. Both mercury sites form regular polyhedrons involving atoms from residues Asp-39, His-69, Cys-73, His-72, Met-225, and Wat-324. The complex formation with mercury seems to disturb the stereochemistry of the residues of the catalytic triad Asp-39, His-69, and Ser-224 appreciably, thus reducing the enzymatic activity of proteinase K to 15%. The electron density in the difference Fourier map shows that the hexapeptide occupies the S1 subsite predominantly and the standard recognition site constituted by Ser-132 to Gly-136 and Gly-100 to Tyr-104 segments is virtually empty. The hexapeptide is held firmly through a series of hydrogen bonds involving protein atoms and water molecules. As a result of complex formation, Asp-39, His-69, Met-225, Ile-220, Ser-219, Thr-223, and Ser-224 residues move appreciably to accommodate the mercury atoms and the hexapeptide. The largest movement is observed for Met-225 which is involved in multiple interactions with both mercury and the hexapeptide. The activity results indicate an inhibition rate of 95%, as a result of the combined effect of mercury and hexapeptide.
About this Structure
1PJ8 is a Single protein structure of sequence from Engyodontium album. Full crystallographic information is available from OCA.
Reference
Structure of a ternary complex of proteinase K, mercury, and a substrate-analogue hexa-peptide at 2.2 A resolution., Saxena AK, Singh TP, Peters K, Fittkau S, Visanji M, Wilson KS, Betzel C, Proteins. 1996 Jun;25(2):195-201. PMID:8811735 Page seeded by OCA on Sat May 3 05:08:36 2008
