3u57

Structures of Alkaloid Biosynthetic Glucosidases Decode Substrate Specificity

spinqualitylabelsall models 3u57, resolution 2.43Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3u57 is a 2 chain structure with sequence from Ophioxylon serpentinum. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CL, DH8 Related: 3u5u, 3u5y Activity: Raucaffricine beta-glucosidase, with EC number 3.2.1.125 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Two similar enzymes with different biosynthetic function in one species have evolved to catalyze two distinct reactions. X-ray structures of both enzymes help reveal their most important differences. The Rauvolfia alkaloid biosynthetic network harbors two O-glucosidases: raucaffricine glucosidase (RG), which hydrolyses raucaffricine to an intermediate downstream in the ajmaline pathway, and strictosidine glucosidase (SG), which operates upstream. RG converts strictosidine, the substrate of SG, but SG does not accept raucaffricine. Now elucidation of crystal structures of RG, inactive RG-E186Q mutant, and its complexes with ligands dihydro-raucaffricine and secologanin reveals that it is the "wider gate" of RG that allows strictosidine to enter the catalytic site, whereas the "slot-like" entrance of SG prohibits access by raucaffricine. Trp392 in RG and Trp388 in SG control the gate shape and acceptance of substrates. Ser390 directs the conformation of Trp392. 3D structures, supported by site-directed mutations and kinetic data of RG and SG, provide a structural and catalytic explanation of substrate specificity and deeper insights into O-glucosidase chemistry. Structures of Alkaloid Biosynthetic Glucosidases Decode Substrate Specificity.,Xia L, Ruppert M, Wang M, Panjikar S, Lin H, Rajendran C, Barleben L, Stockigt J ACS Chem Biol. 2011 Oct 28. PMID:22004291 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Beta-glucosidase

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