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Iron K-edge X-ray absorption spectroscopy of the iron-molybdenum cofactor of nitrogenase from Klebsiella pneumoniae.

ABSTRACT: Iron K-edge X-ray absorption data for the iron-molybdenum cofactor ('FeMoco') from Klebsiella pneumoniae reported here provide the first evidence for long-range structural order in the cofactor [Fe...Fe(Mo) = 0.368 nm in addition to Fe...S = 0.22 nm and Fe...Fe(Mo) = 0.27 nm] and, in contrast with previously published data [Antonio, Teo, Orme-Johnson, Nelson, Groh, Lindahl, Kauzlarich & Averill (1982) J. Am. Chem. Soc. 104, 4703-4705], indicate that most of the iron centres are not co-ordinated to light (oxygen, nitrogen) atoms. This demonstrates that presently available chemical models for FeMoco are inadequate.

SUBMITTER: Arber JM

PROVIDER: S-EPMC1149162 | biostudies-other | 1988 Jun

REPOSITORIES: biostudies-other

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