Structure of the Non-redox-active Tungsten/[4fe:4s] Enzyme Acetylene Hydratase.
From: Fachbereich Biologie, Universität Konstanz, 78457 Konstanz, Germany.
Proceedings of the National Academy of Sciences of the United States of America
- Publish Date: Feb 2007
- ISSN: 0027-8424
- Volume: 104
- Issue: 9
- Pages: 3073-7
- Medium: Print
- Language: English
- Citation (JAMA): Seiffert Grazyna B, Ullmann G Matthias, Messerschmidt Albrecht, et al. Structure of the Non-redox-active Tungsten/[4fe:4s] Enzyme Acetylene Hydratase.. Proc. Natl. Acad. Sci. U.S.A. Feb 2007;104:3073-7
Abstract
The tungsten-iron-sulfur enzyme acetylene hydratase stands out from its class because it catalyzes a nonredox reaction, the hydration of acetylene to acetaldehyde. Sequence comparisons group the protein into the dimethyl sulfoxide reductase family, and it contains a bis-molybdopterin guanine dinucleotide-ligated tungsten atom and a cubane-type [4Fe:4S] cluster. The crystal structure of acetylene hydratase at 1.26 A now shows that the tungsten center binds a water molecule that is activated by an adjacent aspartate residue, enabling it to attack acetylene bound in a distinct, hydrophobic pocket. This mechanism requires a strong shift of pK(a) of the aspartate, caused by a nearby low-potential [4Fe:4S] cluster. To access this previously unrecognized W-Asp active site, the protein evolved a new substrate channel distant from where it is found in other molybdenum and tungsten enzymes.
Mesh Headings (Keywords): Binding Sites, Crystallization, Deltaproteobacteria, Electrostatics, Hydro-Lyases, Models, Molecular, Tungsten
Check for Full Text / PubMed Unique Identifier (PMID): 17360611
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