1det

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=2GP:GUANOSINE-2-MONOPHOSPHATE'>2GP</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene></td></tr>

<tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=CGA:CARBOXYMETHYLATED+GLUTAMIC+ACID'>CGA</scene></td></tr>

<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Ribonuclease_T(1) Ribonuclease T(1)], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.27.3 3.1.27.3] </span></td></tr>

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== 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 &gt; 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<ref>PMID:8679590</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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<div class="pdbe-citations 1det" style="background-color:#fffaf0;"></div>

== References ==

<references/>

[[Category: Ishikawa, K]]

[[Category: Suzuki, E]]

[[Category: Takahashi, K]]

[[Category: Tanokura, M]]

[[Category: Nuclease]]