4dsh | pdb_00004dsh

Crystal structure of reduced UDP-Galactopyranose mutase

spinqualitylabelsall models 4dsh, resolution 2.25Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4dsh is a 2 chain structure with sequence from Trypanosoma cruzi. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: EPE, FDA, SO4, UDP Related: 4dsg Gene: Tc00.1047053507993.160 (Trypanosoma cruzi) Activity: UDP-galactopyranose mutase, with EC number 5.4.99.9 Resources: FirstGlance, OCA, RCSB, PDBsum Publication Abstract from PubMed Chagas disease is a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi. Here we report crystal structures of the galactofuranose biosynthetic enzyme UDP-galactopyranose mutase (UGM) from T. cruzi, which are the first structures of this enzyme from a protozoan parasite. UGM is an attractive target for drug design because galactofuranose is absent in humans but is an essential component of key glycoproteins and glycolipids in trypanosomatids. Analysis of the enzyme-UDP noncovalent interactions and sequence alignments suggests that substrate recognition is exquisitely conserved among eukaryotic UGMs and distinct from that of bacterial UGMs. This observation has implications for inhibitor design. Activation of the enzyme via reduction of the FAD induces profound conformational changes, including a 2.3 A movement of the histidine loop (Gly60-Gly61-His62), rotation and protonation of the imidazole of His62, and cooperative movement of residues located on the si face of the FAD. Interestingly, these changes are substantially different from those described for Aspergillus fumigatus UGM, which is 45% identical to T. cruzi UGM. The importance of Gly61 and His62 for enzymatic activity was studied with the site-directed mutant enzymes G61A, G61P, and H62A. These mutations lower the catalytic efficiency by factors of 10-50, primarily by decreasing k(cat). Considered together, the structural, kinetic, and sequence data suggest that the middle Gly of the histidine loop imparts flexibility that is essential for activation of eukaryotic UGMs. Our results provide new information about UGM biochemistry and suggest a unified strategy for designing inhibitors of UGMs from the eukaryotic pathogens. Crystal Structures of Trypanosoma cruzi UDP-Galactopyranose Mutase Implicate Flexibility of the Histidine Loop in Enzyme Activation.,Dhatwalia R, Singh H, Oppenheimer M, Sobrado P, Tanner JJ Biochemistry. 2012 Jun 5. PMID:22646091 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also UDP-galactopyranose mutase

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