1det
From Proteopedia
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|PDB= 1det |SIZE=350|CAPTION= <scene name='initialview01'>1det</scene>, resolution 1.8Å | |PDB= 1det |SIZE=350|CAPTION= <scene name='initialview01'>1det</scene>, resolution 1.8Å | ||
|SITE= | |SITE= | ||
| - | |LIGAND= <scene name='pdbligand=NA:SODIUM+ION'>NA</scene> and <scene name='pdbligand=2GP:GUANOSINE-2 | + | |LIGAND= <scene name='pdbligand=NA:SODIUM+ION'>NA</scene> and <scene name='pdbligand=2GP:GUANOSINE-2'-MONOPHOSPHATE'>2GP</scene> |
|ACTIVITY= [http://en.wikipedia.org/wiki/Ribonuclease_T(1) Ribonuclease T(1)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.27.3 3.1.27.3] | |ACTIVITY= [http://en.wikipedia.org/wiki/Ribonuclease_T(1) Ribonuclease T(1)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.27.3 3.1.27.3] | ||
|GENE= | |GENE= | ||
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[[Category: signal]] | [[Category: signal]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 23 11:30:09 2008'' |
Revision as of 09:30, 23 March 2008
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| , resolution 1.8Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | and | ||||||
| Activity: | Ribonuclease T(1), with EC number 3.1.27.3 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
RIBONUCLEASE T1 CARBOXYMETHYLATED AT GLU 58 IN COMPLEX WITH 2'GMP
Overview
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.
About this Structure
1DET is a Single protein structure of sequence from Aspergillus oryzae. Full crystallographic information is available from OCA.
Reference
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
Page seeded by OCA on Sun Mar 23 11:30:09 2008
Categories: Aspergillus oryzae | Ribonuclease T(1) | Single protein | Ishikawa, K. | Suzuki, E. | Takahashi, K. | Tanokura, M. | 2GP | NA | Endonuclease | Endoribonuclease | Hydrolase | Nuclease | Signal
