ORCID Profile
0000-0002-2300-3867
Current Organisations
INFN Sezione di Lecce
,
Università di Lecce
,
Istituto tecnico industriale A. Meucci
,
Istituto tecnico statale per Geometri
,
University of Oxford
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Publisher: American Chemical Society (ACS)
Date: 30-05-2003
DOI: 10.1021/BI027380G
Abstract: Lipoxygenases are non-heme iron enzymes, which catalyze the stereo- and regiospecific hydroperoxidation of unsaturated fatty acids. Spectroscopic studies on soybean lipoxygenase have shown that the ferrous form of the enzyme is a mixture of five- and six-coordinate species (40 and 60%, respectively). Addition of substrate leads to a purely six-coordinate form. A series of mutations in the second coordination sphere (Q697E, Q697N, Q495A, and Q495E) were generated, and the structures of the mutants were solved by crystallography [Tomchick et al. (2001) Biochemistry 40, 7509-7517]. While this study clearly showed the contribution of H-bond interactions between the first and the second coordination spheres in catalysis, no correlation with the coordination environment of the Fe(II) was observed. A recent study using density-functional theory [Lehnert and Solomon (2002) J. Biol. Inorg. Chem. 8, 294-305] indicated that coordination flexibility, involving the Asn694 ligand, is regulated via H-bond interactions. In this paper, we investigate the solution structures of the second coordination sphere mutants using CD and MCD spectroscopy since these techniques are more sensitive indicators of the first coordination sphere ligation of Fe(II) systems. Our data demonstrate that the iron coordination environment directly relates to activity, with the mutations that have the ability to form a five-coordinate/six-coordinate mixture being more active. We propose that the H-bond between the weak Asn694 ligand and the Gln697 plays a key role in the modulation of the coordination flexibility of Asn694, and thus, is crucial for the regulation of enzyme reactivity.
Publisher: American Chemical Society (ACS)
Date: 21-10-2011
DOI: 10.1021/JA202549Q
Publisher: American Chemical Society (ACS)
Date: 25-05-2007
DOI: 10.1021/JA068503D
Publisher: Elsevier BV
Date: 07-2016
Publisher: American Chemical Society (ACS)
Date: 27-07-2010
DOI: 10.1021/BI100892W
Publisher: Elsevier
Date: 2003
Publisher: American Chemical Society (ACS)
Date: 26-07-2008
DOI: 10.1021/IC800580F
Location: United States of America
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Michael Neidig.