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1g8k

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(New page: 200px<br /><applet load="1g8k" size="450" color="white" frame="true" align="right" spinBox="true" caption="1g8k, resolution 1.64Å" /> '''CRYSTAL STRUCTURE AN...)
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Revision as of 13:41, 20 November 2007

Image:1g8k.gif

CRYSTAL STRUCTURE ANALYSIS OF ARSENITE OXIDASE FROM ALCALIGENES FAECALIS

Overview

BACKGROUND: Arsenite oxidase from Alcaligenes faecalis NCIB 8687 is a, molybdenum/iron protein involved in the detoxification of arsenic. It is, induced by the presence of AsO(2-) (arsenite) and functions to oxidize, As(III)O(2-), which binds to essential sulfhydryl groups of proteins and, dithiols, to the relatively less toxic As(V)O(4)(3-) (arsenate) prior to, methylation. RESULTS: Using a combination of multiple isomorphous, replacement with anomalous scattering (MIRAS) and multiple-wavelength, anomalous dispersion (MAD) methods, the crystal structure of arsenite, oxidase was determined to 2.03 A in a P2(1) crystal form with two, molecules in the asymmetric unit and to 1.64 A in a P1 crystal form with, four molecules in the asymmetric unit. Arsenite oxidase consists of a, large subunit of 825 residues and a small subunit of approximately 134, residues. The large subunit contains a Mo site, consisting of a Mo atom, bound to two pterin cofactors, and a [3Fe-4S] cluster. The small subunit, contains a Rieske-type [2Fe-2S] site. CONCLUSIONS: The large subunit of, arsenite oxidase is similar to other members of the dimethylsulfoxide, (DMSO) reductase family of molybdenum enzymes, particularly the, dissimilatory periplasmic nitrate reductase from Desulfovibrio, desulfuricans, but is unique in having no covalent bond between the, polypeptide and the Mo atom. The small subunit has no counterpart among, known Mo protein structures but is homologous to the Rieske [2Fe-2S], protein domain of the cytochrome bc(1) and cytochrome b(6)f complexes and, to the Rieske domain of naphthalene 1,2-dioxygenase.

About this Structure

1G8K is a Protein complex structure of sequences from Alcaligenes faecalis with HG, CA, MGD, O, 4MO, F3S, FES and EDO as ligands. Full crystallographic information is available from OCA.

Reference

Crystal structure of the 100 kDa arsenite oxidase from Alcaligenes faecalis in two crystal forms at 1.64 A and 2.03 A., Ellis PJ, Conrads T, Hille R, Kuhn P, Structure. 2001 Feb 7;9(2):125-32. PMID:11250197[[Category: [2fe-2s] cluster]] [[Category: [3fe-4s] cluster]]

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