1ivs: Difference between revisions

[[Image:1ivs.gif|left|200px]]<br /><applet load="1ivs" size="350" color="white" frame="true" align="right" spinBox="true"  

The molecular interactions between valyl-tRNA synthetase (ValRS) and tRNA(Val), with the C34-A35-C36 anticodon, from Thermus thermophilus were studied by crystallographic analysis and structure-based mutagenesis. In the ValRS-bound structure of tRNA(Val), the successive A35-C36 residues (the major identity elements) of tRNA(Val) are base-stacked upon each other, and fit into a pocket on the alpha-helix bundle domain of ValRS. Hydrogen bonds are formed between ValRS and A35-C36 of tRNA(Val) in a base-specific manner. The C-terminal coiled-coil domain of ValRS interacts electrostatically with A20 and hydrophobically with the G19*C56 tertiary base pair. The loss of these interactions by the deletion of the coiled-coil domain of ValRS increased the K(M) value for tRNA(Val) 28-fold and decreased the k(cat) value 19-fold in the aminoacylation. The tRNA(Val) K(M) and k(cat) values were increased 21-fold and decreased 32-fold, respectively, by the disruption of the G18*U55 and G19*C56 tertiary base pairs, which associate the D- and T-loops for the formation of the L-shaped tRNA structure. Therefore, the coiled-coil domain of ValRS is likely to stabilize the L-shaped tRNA structure during the aminoacylation reaction.

1IVS is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermus_thermophilus Thermus thermophilus] with <scene name='pdbligand=VAA:'>VAA</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Valine--tRNA_ligase Valine--tRNA ligase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=6.1.1.9 6.1.1.9] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1IVS OCA].  

[[Category: RSGI, RIKEN Structural Genomics/Proteomics Initiative.]]

[[Category: Sekine, S I.]]

[[Category: Vassylyev, D G.]]

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