Open AccessNew structural insights and molecular‐modelling studies of 4‐methyl‐5‐β‐hydroxyethylthiazole kinase from Pyrococcus horikoshii OT3 ( Ph ThiK)
Author(s) -
Jeyakanthan Jeyaraman,
Thamotharan Subbiah,
Velmurugan Devadasan,
Rao Vaijayanthimala Surya Narayna,
Nagarajan Shanthi,
Shinkai Akeo,
Kuramitsu Seiki,
Yokoyama Shigeyuki
Publication year - 2009
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309109036033
Subject(s) - pyrococcus horikoshii , trimer , biochemistry , stereochemistry , nucleotide , binding site , enzyme , biology , chemistry , gene , organic chemistry , dimer
4‐Methyl‐5‐β‐hydroxyethylthiazole kinase (ThiK) catalyses the phosphorylation of the hydroxyl group of 4‐methyl‐5‐β‐hydroxyethylthiazole. This work reports the first crystal structure of an archaeal ThiK: that from Pyrococcus horikoshii OT3 ( Ph ThiK) at 1.85 Å resolution with a phosphate ion occupying the position of the β‐phosphate of the nucleotide. The topology of this enzyme shows the typical ribokinase fold of an α/β protein. The overall structure of Ph ThiK is similar to those of Bacillus subtilis ThiK ( Bs ThiK) and Enterococcus faecalis V583 ThiK ( Ef ThiK). Sequence analysis of ThiK enzymes from various sources indicated that three‐quarters of the residues involved in interfacial regions are conserved. It also revealed that the amino‐acid residues in the nucleotide‐binding, magnesium ion‐binding and substrate‐binding sites are conserved. Binding of the nucleotide and substrate to the ThiK enzyme do not influence the quaternary association (trimer) as revealed by the crystal structure of Ph ThiK.