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Crystal structure of TT0787 of thermus thermophilus HB8Crystal structure of TT0787 of thermus thermophilus HB8
Structural highlights
Evolutionary ConservationCheck, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe 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. 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[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences |
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