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An ensemble of lipoxygenase structures reveals novel conformations of the Fe coordination sphere
Author(s) -
Pakhomova Svetlana,
Boeglin William E.,
Neau David B.,
Bartlett Sue G.,
Brash Alan R.,
Newcomer Marcia E.
Publication year - 2019
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.3602
Subject(s) - coordination sphere , chemistry , lipoxygenase , stereochemistry , enzyme , oxidoreductase , crystallography , amino acid , crystal structure , biochemistry
The regio‐ and stereo‐specific oxygenation of polyunsaturated fatty acids is catalyzed by lipoxygenases (LOX); both Fe and Mn forms of the enzyme have been described. Structural elements of the Fe and Mn coordination spheres and the helical catalytic domain in which the metal center resides are highly conserved. However, animal, plant, and microbial LOX each have distinct features. We report five crystal structures of a LOX from the fungal plant pathogen Fusarium graminearum . This LOX displays a novel amino terminal extension that provides a wrapping domain for dimerization. Moreover, this extension appears to interfere with the iron coordination sphere, as the typical LOX configuration is not observed at the catalytic metal when the enzyme is dimeric. Instead novel tetra‐, penta‐, and hexa‐coordinate Fe 2+ ligations are apparent. In contrast, a monomeric structure indicates that with repositioning of the amino terminal segment, the enzyme can assume a productive conformation with the canonical Fe 2+ coordination sphere.