Geometric structure determination of N694C lipoxygenase: a comparative near-edge X-ray absorption spectroscopy and extended X-ray absorption fine structure study

Sarangi, Ritimukta, Hocking, Rosalie K., Neidig, Michael L., Benfatto, Maurizio, Holman, Theodore R., Solomon, Edward I., Hodgson, Keith O., and Hedman, Britt (2008) Geometric structure determination of N694C lipoxygenase: a comparative near-edge X-ray absorption spectroscopy and extended X-ray absorption fine structure study. Inorganic Chemistry, 47 (24). pp. 11543-11550.

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Abstract

The mononuclear nonheme iron active site of N694C soybean lipoxygenase (sLO1) has been investigated in the resting ferrous form using a combination of Fe-K-pre-edge, near-edge (using the minuit X-ray absorption near-edge full multiple-scattering approach), and extended X-ray absorption fine structure (EXAFS) methods. The results indicate that the active site is six-coordinate (6C) with a large perturbation in the first-shell bond distances in comparison to the more ordered octahedral site in wild-type sLO1. Upon mutation of the asparigine to cystiene, the short Fe-O interaction with asparigine is replaced by a weak Fe-(H₂O), which leads to a distorted 6C site with an effective 5C ligand field. In addition, it is shown that near-edge multiple scattering analysis can give important three-dimensional structural information, which usually cannot be accessed using EXAFS analysis. It is further shown that; relative to EXAFS, near-edge analysis is more sensitive to partial coordination numbers and can be potentially used as a tool for structure determination in a mixture of chemical species.

Item ID: 28892
Item Type: Article (Research - C1)
ISSN: 1520-510X
Date Deposited: 21 Aug 2013 09:22
FoR Codes: 03 CHEMICAL SCIENCES > 0302 Inorganic Chemistry > 030201 Bioinorganic Chemistry @ 100%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970103 Expanding Knowledge in the Chemical Sciences @ 100%
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