Domain-specific recruitment of amide amino acids for protein synthesis.

The formation of aminoacyl-transfer RNA is a crucial step in ensuring the accuracy of protein synthesis. Despite the central importance of this process in all living organisms, it remains unknown how archaea and some bacteria synthesize Asn-tRNA and Gln-tRNA. These amide aminoacyl-tRNAs can be formed by the direct acylation of tRNA, catalysed by asparaginyl-tRNA synthetase and glutaminyl-tRNA synthetase, respectively.

The adaptor hypothesis revisited.

As originally postulated in Crick's Adaptor hypothesis, the faithful synthesis of proteins from messenger RNA is dependent on the presence of perfectly acylated tRNAs. The hypothesis also suggested that each aminoacyl-tRNA would be made by a unique enzyme. Recent data have now forced a revision of this latter point, with an increasingly diverse array of enzymes and pathways being implicated in aminoacyl-tRNA synthesis.

Cysteine biosynthesis pathway in the archaeon Methanosarcina barkeri encoded by acquired bacterial genes?

The pathway of cysteine biosynthesis in archaea is still unexplored. Complementation of a cysteine auxotrophic Escherichia coli strain NK3 led to the isolation of the Methanosarcina barkeri cysK gene [encoding O-acetylserine (thiol)-lyase-A], which displays great similarity to bacterial cysK genes. Adjacent to cysK is an open reading frame orthologous to bacterial cysE (serine transacetylase) genes.

Archaeal aminoacyl-tRNA synthesis: diversity replaces dogma.

Accurate aminoacyl-tRNA synthesis is essential for faithful translation of the genetic code and consequently has been intensively studied for over three decades. Until recently, the study of aminoacyl-tRNA synthesis in archaea had received little attention. However, as in so many areas of molecular biology, the advent of archaeal genome sequencing has now drawn researchers to this field.