1iaa
From Proteopedia
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CRYSTAL STRUCTURES, SPECTROSCOPIC FEATURES, AND CATALYTIC PROPERTIES OF COBALT(II), COPPER(II), NICKEL(II), AND MERCURY(II) DERIVATIVES OF THE ZINC ENDOPEPTIDASE ASTACIN. A CORRELATION OF STRUCTURE AND PROTEOLYTIC ACTIVITY
Overview
The catalytic zinc ion of astacin, a prototypical metalloproteinase from, crayfish, has been substituted by Co(II), Cu(II), Hg(II), and Ni(II) in, order to probe the role of the metal for both catalysis and structure., Compared to Zn(II)-astacin, Co(II)- and Cu(II)-astacin display enzymatic, activities of about 140 and 37%, respectively, while Ni(II)- and, Hg(II)-astacin are almost inactive. The electron paramagnetic resonance, spectrum of Cu(II)-astacin is typical of 5-fold coordinated copper(II), and its intense absorption maxima at 445 and 325 nm are probably due to, ligand-metal charge-transfer transitions involving Tyr-149. This residue, had been identified previously by x-ray crystallography of the zinc enzyme, as a zinc ligand, in addition to three imidazoles and a glutamic, acid-bound water molecule. We present now the refined high-resolution, x-ray crystal structures of Cu(II)-, Co(II)-, and Ni(II)-astacin, which, exhibit a virtually identical protein framework to the previously analyzed, structures of Zn(II)-, apo-, and Hg(II)-astacin. In Co(II)- and, Cu(II)-astacin, the metal is penta-coordinated similarly to the native, zinc enzyme. In the Ni(II) derivative, however, an additional solvent, molecule expands the metal coordination sphere to a distorted octahedral, ligand geometry, while in Hg(II)-astacin, no ordered solvent molecule at, all is observed in the inner coordination sphere of the metal. This, indicates a close correlation between catalytic properties and, ground-state metal coordination of astacin.
About this Structure
1IAA is a Single protein structure of sequence from Astacus astacus with CU as ligand. Active as Astacin, with EC number 3.4.24.21 Full crystallographic information is available from OCA.
Reference
Crystal structures, spectroscopic features, and catalytic properties of cobalt(II), copper(II), nickel(II), and mercury(II) derivatives of the zinc endopeptidase astacin. A correlation of structure and proteolytic activity., Gomis-Ruth FX, Grams F, Yiallouros I, Nar H, Kusthardt U, Zwilling R, Bode W, Stocker W, J Biol Chem. 1994 Jun 24;269(25):17111-7. PMID:8006015
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