5b51

Crystal structure of heme binding protein HmuT R242A mutant

spinqualitylabelsall models 5b51, resolution 1.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5b51 is a 1 chain structure with sequence from Corgl. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: HEM Related: 5az3, 5b4z, 5b50 Gene: Cgl0389 (CORGL) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Corynebacteria contain a heme uptake system encoded in hmuTUV genes, in which HmuT protein acts as a heme binding protein to transport heme to the cognate transporter HmuUV. The crystal structure of HmuT from Corynebacterium glutamicum (CgHmuT) reveals that heme is accommodated in the central cleft with His141 and Tyr240 as the axial ligands and that Tyr240 forms a hydrogen bond with Arg242. In this work, the crystal structures of H141A, Y240A, and R242A mutants were determined to understand the role of these residues for the heme binding of CgHmuT. Overall and heme environmental structures of these mutants were similar to those of the wild type, suggesting that there is little conformational change in the heme-binding cleft during heme transport reaction with binding and the dissociation of heme. A loss of one axial ligand or the hydrogen bonding interaction with Tyr240 resulted in an increase in the redox potential of the heme for CgHmuT to be reduced by dithionite, though the wild type was not reduced under physiological conditions. These results suggest that the heme environmental structure stabilizes the ferric heme binding in CgHmuT, which will be responsible for efficient heme uptake under aerobic conditions where Corynebacteria grow. Structural Characterization of Heme Environmental Mutants of CgHmuT that Shuttles Heme Molecules to Heme Transporters.,Muraki N, Kitatsuji C, Ogura M, Uchida T, Ishimori K, Aono S Int J Mol Sci. 2016 May 27;17(6). pii: E829. doi: 10.3390/ijms17060829. PMID:27240352 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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