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Comparative study of subunits of phenylalanyl‐tRNA synthetase from Escherichia coli and Thermus thermophilus
Author(s) -
Bobkova Ekaterina V.,
Mashanov-Golikov Anton V.,
Wolfson Aleksey,
Ankilova Valenti.,
Lavrik Olga I.
Publication year - 1991
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(91)81234-y
Subject(s) - thermus thermophilus , thermus aquaticus , aminoacylation , enzyme , escherichia coli , biochemistry , thermophile , transfer rna , chemistry , fast protein liquid chromatography , protein subunit , thermus , biology , stereochemistry , rna , gene
FPLC separation of α‐ and β‐subunits of phenylalanyl‐tRNA synthetases from E. coli MRE‐600 and Thermus thermophilus HB8 has been carried out in the presence of urea. Native α‐subunits of both enzymes were primarily α 2 ‐dimers and tended to aggregate. Most E. coli enzyme β‐subunits were monomeric and only a small fraction was represented by β 2 ‐dimers. All thermophilic β‐subunits were β‐dimers. It was shown that monomers and all forms of homologous subunits had no catalytic activity in tRNA Phe aminoacylation. For the enzymes and their subunits, titration curves were obtained and isoelectric points were determined. The comparison of the relative surface charges indicated similarity of the surfaces of entire enzymes and the corresponding β‐subunits. α‐Subunits displayed a distinctly different pH dependence of the surface charge. A spatial model of the oligomeric structure and a putative mechanism for its formation are discussed.