2ux9
From Proteopedia
Crystal structure of the T. thermophilus dodecin R65A mutant
Structural highlights
FunctionDODEC_THET8 May function as storage protein that sequesters various flavins and other cofactors, thereby protecting the cell against undesirable reactions mediated by the free cofactors. Binds and sequesters FMN, FAD, lumiflavin and lumichrome, and can also bind coenzyme A.[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedDodecins are so far the smallest known flavoproteins (68-71 amino acids) and are most likely involved in prokaryotic flavin storage. The dodecin monomers adopt a simple betaalphabetabeta-fold and assemble to hollow sphere-like dodecameric complexes. Flavin binding by the dodecin from Thermus thermophilus showed a 1:1 stoichiometry and apparent dissociation constants in the submicromolar to nanomolar range as characterized by isothermal titration calorimetry and fluorescence titrations. The x-ray structures of the flavin-prebound and FMN-reconstituted state of the T. thermophilus dodecin revealed binding of FMN dimers in a novel si-si- rather than the re-re- orientation of their isoalloxazine moieties as found before in an archaeal dodecin. Electron paramagnetic resonance studies demonstrated that upon reduction the excess electron is localized only on one flavin, thus making dodecin-bound flavins highly refractory to redox chemistry. Besides FMN dimers, trimers of coenzyme A are additionally bound to this eubacterial dodecin along the 3-fold symmetry face II of the dodecin complex. Therefore, dodecins can act as bifunctional cofactor storage proteins that sequester catalytic cofactors in prokaryotes very efficiently in an aggregated and unreactive state. The dodecin from Thermus thermophilus, a bifunctional cofactor storage protein.,Meissner B, Schleicher E, Weber S, Essen LO J Biol Chem. 2007 Nov 9;282(45):33142-54. Epub 2007 Sep 11. PMID:17855371[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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