Aminoacylation inSulfolobus acidocaldariusand in methanogenic and halophilic archaebacteria

Abstract

Phenylalanyl‐tRNA synthetase (PRS) from the sulphur‐metabolizing thermoacidophilic archaebacterium Sulfolobus acidocaldarius has been purified 150‐fold using different chromatographic steps. The enzyme has a Mr of 270 000 and exhibits considerable thermostability in a temperature range up to 90°C with optimal activity at 70°C. Conservation of antigenic determinants could not be detected by antibodies against various PRS of all primary kingdoms. As a further means to detect traits of phylogenetic relationship, the cross‐species reactivity between PRS and tRNAs of organisms from the three branches of archaebacteria and from all primary kingdoms reveals the group character of all 3 branches of the archaebacterial domain, the sulphur‐metabolizing, methanogenic and halophilic archaebacteria.

A single gene of chloroplast origin codes for mitochondrial and chloroplastic methionyl–tRNA synthetase in Arabidopsis thaliana

“…Purification and biochemical characterization of several plant aaRSs have been reported (4)(5)(6)(7). These studies established that, in general, plant aaRSs can be classified into two groups, based on their substrate specificity: (i) the cytosolic enzymes that most efficiently aminoacylate plant or yeast cytosolic tRNAs; and (ii) the organellar enzymes that aminoacylate organelle or Escherichia coli tRNAs (8).…”