1iuh
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(New page: 200px<br /><applet load="1iuh" size="450" color="white" frame="true" align="right" spinBox="true" caption="1iuh, resolution 2.50Å" /> '''Crystal structure of...)
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Revision as of 20:26, 24 November 2007
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Crystal structure of TT0787 of thermus thermophilus HB8
Overview
The 2'-5' RNA ligase family members are bacterial and archaeal RNA ligases, that ligate 5' and 3' half-tRNA molecules with 2',3'-cyclic phosphate and, 5'-hydroxyl termini, respectively, to the product containing the 2'-5', phosphodiester linkage. Here, the crystal structure of the 2'-5' RNA, ligase protein from an extreme thermophile, Thermus thermophilus HB8, was, solved at 2.5A resolution. The structure of the 2'-5' RNA ligase, superimposes well on that of the Arabidopsis thaliana cyclic, phosphodiesterase (CPDase), which hydrolyzes ADP-ribose 1",2"-cyclic, phosphate (a product of the tRNA splicing reaction) to the monoester, ADP-ribose 1"-phosphate. Although the sequence identity between the two, proteins is remarkably low (9.3%), the 2'-5' RNA ligase and CPDase, structures have two HX(T/S)X motifs in their corresponding positions. The, HX(T/S)X motifs play important roles in the CPDase activity, and are, conserved in both the CPDases and 2'-5' RNA ligases. Therefore, the, catalytic mechanism of the 2'-5' RNA ligase may be similar to that of the, CPDase. On the other hand, the electrostatic potential of the cavity of, the 2'-5' RNA ligase is positive, but that of the CPDase is negative., Furthermore, in the CPDase, two loops with low B-factors cover the cavity., In contrast, in the 2'-5' RNA ligase, the corresponding loops form an open, conformation and are flexible. These characteristics may be due to the, differences in the substrates, tRNA and ADP-ribose 1",2"-cyclic phosphate.
About this Structure
1IUH is a Single protein structure of sequence from Thermus thermophilus. Full crystallographic information is available from OCA.
Reference
Crystal structure of the 2'-5' RNA ligase from Thermus thermophilus HB8., Kato M, Shirouzu M, Terada T, Yamaguchi H, Murayama K, Sakai H, Kuramitsu S, Yokoyama S, J Mol Biol. 2003 Jun 20;329(5):903-11. PMID:12798681
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