cd00774

Glycyl-tRNA synthetase (GlyRS)-like class II core catalytic domain. GlyRS functions as a homodimer in eukaryotes, archaea and some bacteria and as a heterotetramer in the remainder of prokaryotes. It is responsible for the attachment of glycine to the 3' OH group of ribose of the appropriate tRNA. This domain is primarily responsible for ATP binding and hydrolysis. This alignment contains only sequences from the GlyRS form which homodimerizes. The heterotetramer glyQ is in a different family of class II aaRS. Class II assignment is based upon its structure and the presence of three characteristic sequence motifs. This domain is also found at the N-terminus of the accessory subunit of mitochondrial polymerase gamma (Pol gamma b). Pol gamma b stimulates processive DNA synthesis and is functional as a homodimer, which can associate with the catalytic subunit Pol gamma alpha to form a heterotrimer. Despite significant both structural and sequence similarity with GlyRS, Pol gamma b lacks conservation of several class II functional residues.