1ahj
From Proteopedia
|
NITRILE HYDRATASE
Overview
BACKGROUND: Nitrile hydratases are unusual metalloenzymes that catalyze, the hydration of nitriles to their corresponding amides. They are used as, biocatalysts in acrylamide production, one of the few commercial scale, bioprocesses, as well as in environmental remediation for the removal of, nitriles from waste streams. Nitrile hydratases are composed of two, subunits, alpha and beta, and they contain one iron atom per alphabeta, unit. We have determined the crystal structure of photoactivated, iron-containing nitrile hydratase from Rhodococcus sp. R312 to 2.65 A, resolution as a first step in the elucidation of its catalytic mechanism., RESULTS: The alpha subunit consists of a long N-terminal arm and a, C-terminal domain that forms a novel fold. This fold can be described as a, four layered structure, alpha-beta-beta-alpha, with unusual connectivities, between the beta strands. The beta subunit also contains a long N-terminal, extension, a helical domain, and a C-terminal domain that folds into a, beta roll. The two subunits form a tight heterodimer that is the, functional unit of the enzyme. The active site is located in a cavity at, the subunit-subunit interface. The iron centre is formed by residues from, the alpha subunit only-three cysteine thiolates and two mainchain amide, nitrogen atoms are ligands. CONCLUSIONS: Nitrile hydratases contain a, novel iron centre with a structure not previously observed in proteins; it, resembles a hybrid of the iron centres of heme and Fe-S proteins. The, low-spin electronic configuration presumably results in part from two, Fe-amide nitrogen bonds. The structure is consistent with the metal ion, having a role as a Lewis acid in the catalytic reaction.
About this Structure
1AHJ is a Protein complex structure of sequences from Rhodococcus sp. r312 with as ligand. Active as Nitrile hydratase, with EC number 4.2.1.84 Known structural/functional Sites: , , and . Full crystallographic information is available from OCA.
Reference
Crystal structure of nitrile hydratase reveals a novel iron centre in a novel fold., Huang W, Jia J, Cummings J, Nelson M, Schneider G, Lindqvist Y, Structure. 1997 May 15;5(5):691-9. PMID:9195885
Page seeded by OCA on Sun Feb 3 09:30:19 2008
