Role of methionine 56 in the control of the oxidation-reduction potentials of the Clostridium beijerinckii flavodoxin: effects of substitutions by aliphatic amino acids and evidence for a role of sulfur-flavin interactions

Biochemistry
L J Druhan, R P Swenson

Abstract

Flavodoxins are small electron transferases that participate in low-potential electron transfer pathways. The flavodoxin protein is able to separate the two redox couples of the noncovalently bound flavin mononucleotide (FMN) cofactor through the differential thermodynamic stabilization or destabilization of each of its redox states. In the flavodoxin from Clostridium beijerinckii, the sulfur atom of methionine 56 is in direct contact with the re or inner face of the isoalloxazine ring of the FMN cofactor. In this study, evidence was sought for a possible role for sulfur-aromatic (flavin) interactions in the regulation of one-electron reduction potentials in flavoproteins. Met56 was systematically replaced with all the naturally occurring aliphatic amino acids by site-directed mutagenesis. Replacement of Met56 with alanine or glycine increased the midpoint potentials at pH 7 for the oxidized-semiquinone couple by up to 20 mV compared to that of the wild type, while replacement by the longer chain aliphatic residues decreased the midpoint potential by >30 mV. The midpoint potential for the semiquinone-hydroquinone couple was less negative than that for the wild type for all the mutants, increasing by as much as 90 mV for the M56...Continue Reading

References

Feb 1, 1996·Biochemical Society Transactions·S G MayhewS M Geoghegan
Jun 1, 1953·The Biochemical Journal·L G WHITBY
Jul 20, 1933·The Journal of General Physiology·L Michaelis, E S Hill

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Citations

Mar 11, 2009·Biochemistry·Uchechi E Ukaegbu, Amy C Rosenzweig
Jan 5, 2002·Antioxidants & Redox Signaling·R J Stanley
May 2, 2001·Proceedings of the National Academy of Sciences of the United States of America·C MuraD S Eisenberg
Sep 1, 2009·Nature Chemical Biology·Brian D ZoltowskiBrian R Crane
Oct 2, 2007·Archives of Biochemistry and Biophysics·Susana FragoMilagros Medina
Mar 4, 2015·Journal of Medicinal Chemistry·Brett R BenoNicholas A Meanwell
Sep 18, 2012·Biochimica Et Biophysica Acta·Isaias LansMilagros Medina
Apr 19, 2003·The Journal of Biological Chemistry·Anabel LostaoJavier Sancho
Mar 29, 2000·The Journal of Biological Chemistry·A LostaoJ Sancho
Mar 14, 2018·The Journal of Physical Chemistry. B·Esam A Orabi, Ann M English

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