Download MendeleyStructure of the non-redox-active tungsten/[4Fe:4S] enzyme acetylene hydratase
Seiffert, G.B., Ullmann, G.M., Messerschmidt, A., Schink, B., Kroneck, P.M.H., Einsle, O.(2007) Proc Natl Acad Sci U S A 104: 3073-3077
- PubMed: 17360611
- DOI: https://doi.org/10.1073/pnas.0610407104
- Primary Citation of Related Structures:
2E7Z - PubMed 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.
Organizational Affiliation:
Fachbereich Biologie, Universit?t Konstanz, 78457 Konstanz, Germany.
