1xty
From Proteopedia
|
Crystal structure of Sulfolobus solfataricus peptidyl-tRNA hydrolase
Overview
The 3-D structure of the peptidyl-tRNA hydrolase from the archaea, Sulfolobus solfataricus has been solved at 1.8 A resolution. Homologues of, this enzyme are found in archaea and eucarya. Bacteria display a different, type of peptidyl-tRNA hydrolase that is also encountered in eucarya. In, solution, the S. solfataricus hydrolase behaves as a dimer. In agreement, the crystalline structure of this enzyme indicates the formation of a, dimer. Each protomer is made of a mixed five-stranded beta-sheet, surrounded by two groups of two alpha-helices. The dimer interface is, mainly formed by van der Waals interactions between hydrophobic residues, belonging to the two N-terminal alpha1 helices contributed by two, protomers. Site-directed mutagenesis experiments were designed for probing, the basis of specificity of the archaeal hydrolase. Among the strictly, conserved residues within the archaeal/eucaryal peptidyl-tRNA hydrolase, family, three residues, K18, D86, and T90, appear of utmost importance for, activity. They are located in the N-part of alpha1 and in the beta3-beta4, loop. K18 and D86, which form a salt bridge, might play a role in the, catalysis thanks to their acid and basic functions, whereas the OH group, of T90 could act as a nucleophile. These observations clearly distinguish, the active site of the archaeal/eucaryal hydrolases from that of the, bacterial/eucaryal ones, where a histidine is believed to serve as the, catalytic base.
About this Structure
1XTY is a Single protein structure of sequence from Pyrococcus abyssi with SO4 as ligand. Active as Aminoacyl-tRNA hydrolase, with EC number 3.1.1.29 Full crystallographic information is available from OCA.
Reference
Crystal structure at 1.8 A resolution and identification of active site residues of Sulfolobus solfataricus peptidyl-tRNA hydrolase., Fromant M, Schmitt E, Mechulam Y, Lazennec C, Plateau P, Blanquet S, Biochemistry. 2005 Mar 22;44(11):4294-301. PMID:15766258
Page seeded by OCA on Wed Nov 21 06:20:33 2007
