1ptk
From Proteopedia
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| , resolution 2.4Å | |||||||
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| Ligands: | , | ||||||
| Activity: | Peptidase K, with EC number 3.4.21.64 | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
STUDIES ON THE INHIBITORY ACTION OF MERCURY UPON PROTEINASE K
Overview
In proteinase K, Cys73 is located "below" the imidazole of the active site His69. In a 2.4-A resolution x-ray crystal structure of the complex formed between the enzyme and HgAc2, two Hg(II) positions are found: a fully occupied site, covalently bound to Cys73 (S gamma), which disrupts the catalytic triad (Asp39-His69-Ser224), and a 2-fold disordered (25 and 35% occupancy), noncovalent complexation to His72, Cys73, and Thr76 of lower affinity. The enzyme is inhibited noncompetitively at low concentrations and competitively above stoichiometric concentrations of Hg(II), but it retains 7% residual activity. This can be rationalized if the molecule is flexible enough to permit transient formation of the catalytic triad. Except for the active site, only minor structural changes are observed upon binding of Hg(II), but the thermal stability is reduced by 4 degrees C.
About this Structure
1PTK is a Single protein structure of sequence from Engyodontium album. Full crystallographic information is available from OCA.
Reference
Studies on the inhibitory action of mercury upon proteinase K., Muller A, Saenger W, J Biol Chem. 1993 Dec 15;268(35):26150-4. PMID:8253733
Page seeded by OCA on Sun Mar 30 23:04:23 2008
