tRNA-binding arm superfamily

This entry represents an alpha-helical tRNA-binding arm found in class I and II aminoacyl-tRNA synthetase enzymes, as well as in the methicillin resistance protein FemA.

The tRNA-binding arm domain is conserved between class I and class II aminoacyl-tRNA synthetase enzymes , consisting of two alpha helices in an antiparallel hairpin with a left-handed twist. The appended tRNA-binding domains recognize a small number of nucleotides that are conserved specifically in each cognate tRNA species for the discrimination between the cognate and noncognate tRNAs [12554880]. These nucleotides are called identity elements, and constitute the identity set. The tRNA-binding arm occurs as the C-terminal domain in some class I enzymes, such as valyl-tRNA synthetase, and as the N-terminal domain in some class II enzymes, such as phenylalanyl-tRNA synthetase.

The methicillin resistance protein, FemA (factors essential for methicillin resistance), contains a probable tRNA-binding arm that is similar in structure to those found in tRNA synthetases. In FemA, the tRNA-binding arm is inserted into the C-terminal NAT-like domain, and is thought to bind tRNA-glycine. FemA, along with FemB and FemX, plays a vital role in peptidoglycan biosynthesis specific to Staphylococci [12176388].