1uca

Crystal structure of the Ribonuclease MC1 from bitter gourd seeds complexed with 2'-UMP

spinqualitylabelsall models 1uca, resolution 1.48Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1uca is a 1 chain structure with sequence from Momordica charantia. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.48Å Ligands: U2P Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function RNMC1_MOMCH Ribonuclease cleaving preferentially the 5'-side of uridine. 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 PubMed Ribonuclease MC1 (RNase MC1) isolated from seeds of bitter gourd (Momordica charantia) consists of 190 amino acids and is characterized by a preferential cleavage at the 5'-side of uridine. This uridine specificity distinguishes RNase MC1 from other enzymes belonging to the RNase T2 family. The three-dimensional structures of RNase MC1, in a complex with either 2'-UMP or 3'-UMP, were determined at 1.48 and 1.77 A resolutions, respectively. The side chains of Gln9 and Asn71 interact with O4 and N3, respectively, of the uracil base by hydrogen bondings. In addition, the uracil base is sandwiched by the hydrophobic side chains of Leu73 and Phe80. Compared with these amino acid residues and corresponding residues in RNases in the RNase T2 family, Gln9 and Phe80 are highly conserved in the RNases in T2 family, while Asn71 and Leu73 in RNase MC1 are variant in sequences. It is thus likely that interactions of the side chains of Asn71 and Leu73 with the uracil base are responsible for the absolute uridine specificity of RNase MC1. Site-directed mutagenesis experiments showed that replacement of Asn by Thr decreased both the catalytic efficiency and the binding affinity by 2.3- and 7.0-fold, respectively, and substitution of Leu73 for Ala predominantly decreased the binding affinity by 14. 5-fold, compared with findings in case of wild-type RNase MC1. It is thus demonstrated that Asn71 and Leu73 play an essential role in uridine preference for RNase MC1. Crystal structures of the ribonuclease MC1 from bitter gourd seeds, complexed with 2'-UMP or 3'-UMP, reveal structural basis for uridine specificity.,Suzuki A, Yao M, Tanaka I, Numata T, Kikukawa S, Yamasaki N, Kimura M Biochem Biophys Res Commun. 2000 Aug 28;275(2):572-6. PMID:10964705 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ribonuclease 3D structures

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