This Sandbox is Reserved from 06/12/2018, through 30/06/2019 for use in the course "Structural Biology" taught by Bruno Kieffer at the University of Strasbourg, ESBS. This reservation includes Sandbox Reserved 1480 through Sandbox Reserved 1543.
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Flavocytochrome b(2) (Arg289Lys mutant) from Saccharomyces cerevisiae is an oxidoreductase that couples dehydrogenation of L-lactate to cytochrome c reduction by electron transfer. It is one step of the bacterial lactate metabolic pathway.
Reaction
Similar oxidants that can be used to perform the reaction in vitro are ferricyanide, phenozine methosulfate and quinone (experiment first performed 1963 by Nygaard[1], later in 1966 described by Symons and Burgoyne][2].
The Yeasts L-Lactate Dehydrogenase can be inhibited by heavy metals, oxygen, glycerate, oxalate, malate, phenylpyruvate and fatty acids [Nygaard 1963][3].
The Enzyme shows a specificity for L-lactate but none for the D-isomer or -hydroxybutyrate.
Relevance
While the function of cytochrome b2 is to couple L-lactate dehydrogenation to cytochrome c reduction; the mutant ARG289LYS is changing the kinetics of the reactions. It is rising the Ki of several components in comparison to the wild-type, while kcat and KM are also changed by a factor of 10. It changes also the induction by L-lactate.
R289K-b(2)
eing a component of the mitochondrial inter membrane space
Structural highlights
Global Symmetry Cyclic - C4
Global Stoichiometry Homotetramer A4
Flavocytochrome b(2) is a tetrameric enzyme [Jacq and Lederer, 1972]. Each of the four identical subunits is composed by one single polypeptide chain.
Each subunit contains a binding site for the selectively non-covalently binding of the cofactor FM3- (FlavinMonoNucleotide),
The amino acid sequence in the heme binding region was first determined by Guidard et al. (1974).
For every subunit the crystallized preparation analysis determined a molecular weight of the chain of 36 kD [Appleby and Morton] and the chain of 21 kD [Jacq and Lederer, 1974].
This is a sample scene created with SAT to color by Group, and another to make a transparent representation of the protein. You can make your own scenes on SAT starting from scratch or loading and editing one of these sample scenes.
↑NYGAARD AP. Various forms of D- and L-lactate dehydrogenases in yeast. Ann N Y Acad Sci. 1961 Nov 2;94:774-9. PMID:14480786
↑Hanson, R. M., Prilusky, J., Renjian, Z., Nakane, T. and Sussman, J. L. (2013), JSmol and the Next-Generation Web-Based Representation of 3D Molecular Structure as Applied to Proteopedia. Isr. J. Chem., 53:207-216. doi:https://dx.doi.org/10.1002/ijch.201300024
↑Herraez A. Biomolecules in the computer: Jmol to the rescue. Biochem Mol Biol Educ. 2006 Jul;34(4):255-61. doi: 10.1002/bmb.2006.494034042644. PMID:21638687 doi:10.1002/bmb.2006.494034042644