3syu

Re-refined coordinates for pdb entry 1det - ribonuclease T1 carboxymethylated at GLU 58 in complex with 2'GMP

spinqualitylabelsall models 3syu, resolution 1.95Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3syu is a 1 chain structure with sequence from Aspergillus oryzae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: 2GP, NA, UNX NonStd Res: CGA Related: 1det Activity: Ribonuclease T(1), with EC number 3.1.27.3 Resources: FirstGlance, OCA, RCSB, PDBsum Publication Abstract from PubMed The carboxymethylation of RNase T1 at the gamma-carboxyl group of Glu58 leads to a complete loss of the enzymatic activity while it retains substrate-binding ability. Accompanying the carboxymethylation, RNase T1 undergoes a remarkable thermal stabilization of 9 degrees C in the melting temperature (Tm). In order to clarify the inactivation and stabilization mechanisms of RNase T1 by carboxymethylation, the crystal structure of carboxymethylated RNase T1 (CM-RNase T1) complexed with 2'-GMP was determined at 1.8 A resolution. The structure, including 79 water molecules and two Na+, was refined to an R factor of 0.194 with 10 354 reflections > 1 sigma (F). The carboxyl group of CM-Glu58, which locates in the active site, occupies almost the same position as the phosphate group of 2'-GMP in the crystal structure of intact RNase T1.2'-GMP complex. Therefore, the phosphate group of 2'-GMP cannot locate in the active site but protrudes toward the solvent. This forces 2'-GMP to adopt an anti form, which contrasts with the syn form in the crystal of the intact RNase T1.2'-GMP complex. The inaccessibility of the phosphate group to the active site can account for the lack of the enzymatic activity in CM-RNase T1. One of the carboxyl oxygen atoms of CM-Glu58 forms two hydrogen bonds with the side-chains of Tyr38 and His40. These hydrogen bonds are considered to mainly contribute to the higher thermal stability of CM-RNase T1. Another carboxyl oxygen atoms of CM-Glu58 is situated nearby His40 and Arg77. This may provide additional electrostatic stabilization. Crystal structure of ribonuclease T1 carboxymethylated at Glu58 in complex with 2'-GMP.,Ishikawa K, Suzuki E, Tanokura M, Takahashi K Biochemistry. 1996 Jun 25;35(25):8329-34. PMID:8679590 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ribonuclease Temp

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