The T-arm or T-loop is a specialized region on the tRNA molecule which acts as a special recognition site for the ribosome to form a tRNA-ribosome complex during protein biosynthesis or translation (biology).
The T-arm has two components to it; the T-stems and the T-loop.
Organisms with T-loop lacking tRNA exhibit a much lower level of aminoacylation and EF-Tu-binding than in organisms which have the native tRNA.
The T-loop motif has been identified as a ubiquitous structural element in a number of noncoding RNAs.[1] At least one other instance of the T-loop, found in rRNA, also carries the m5U modifictaion.[3]