1PTK

STUDIES ON THE INHIBITORY ACTION OF MERCURY UPON PROTEINASE K

Summary for 1PTK

• Entry DOI: 10.2210/pdb1ptk/pdb
• Descriptor: PROTEINASE K, MERCURY (II) ION, CALCIUM ION, ... (4 entities in total)
• Functional Keywords: hydrolase(serine proteinase)
• Biological source: Engyodontium album
• Total number of polymer chains: 1
• Total formula weight: 29372.04

Authors

Mueller, A.,Saenger, W. (deposition date: 1993-04-07, release date: 1994-01-31, Last modification date: 2024-10-30)

Primary citation

Muller, A.,Saenger, W.
Studies on the inhibitory action of mercury upon proteinase K.
J.Biol.Chem., 268:26150-26154, 1993

PubMed Abstract: 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.

PubMed: 8253733

Experimental method

X-RAY DIFFRACTION (2.4 Å)