Download MendeleyCrystal 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.(2003) J Mol Biol 329: 903-911
- PubMed: 12798681
- DOI: https://doi.org/10.1016/s0022-2836(03)00448-0
- Primary Citation of Related Structures:
1IUH - PubMed Abstract:
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.
Organizational Affiliation:
RIKEN Genomic Sciences Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan.
