Phenylalanyl-tRNA synthetase from the archaeon Methanobacterium thermoautotrophicum is an (alpha beta)(2) heterotetrameric protein

Phenylalanyl-tRNA synthetase from the methanogenic archaeon Methanobacteriu m thermoautotrophicum was purified to apparent homogeneity. The catalytical ly active enzyme is a heterotetramer composed of two subunits, alpha and be ta. N-terminal sequence data were obtained for both subunits and the open r eading frames MT770 and MT742 of the genome sequence of M. thermoautotrophi cum were identified as coding for these proteins. Two ORFs with similarity to non-archaeal PheRSs alpha-subunits had previously been found in the geno me sequence, but these results show that only one of them, MT742, is part o f the active PheRS. (C) Societe francaise de biochimie et biologie molecula ire/Editions scientifiques et medicales Elsevier SAS.