The D arm is a feature in the
tertiary structure
Protein tertiary structure is the three dimensional shape of a protein. The tertiary structure will have a single polypeptide chain "backbone" with one or more protein secondary structures, the protein domains. Amino acid side chains may i ...
of
transfer RNA
Transfer RNA (abbreviated tRNA and formerly referred to as sRNA, for soluble RNA) is an adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length (in eukaryotes), that serves as the physical link between the mRNA and the amino ...
(tRNA). It is composed of the two D stems and the D loop. The D loop contains the base
dihydrouridine, for which the arm is named.
The D loop's main function is that of recognition. It is widely believed that it acts as a recognition site for
aminoacyl-tRNA synthetase, an
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...
involved in the
aminoacylation
Aminoacylation is the process of adding an aminoacyl group to a compound.
See also
* Acylation
* tRNA aminoacylation
* Transfer RNA-like structures
References
Organic reactions
{{Reaction-stub ...
of the tRNA molecule.
The D stem is also believed to have a recognition role although this has yet to be verified.
It is a highly variable region and is notable for its unusual conformation due to the over-crowding on one of the guanosine
Guanosine (symbol G or Guo) is a purine nucleoside comprising guanine attached to a ribose ( ribofuranose) ring via a β-N9- glycosidic bond. Guanosine can be phosphorylated to become guanosine monophosphate (GMP), cyclic guanosine monophosphate ...
residues. It appears to play a large role in the stabilization of the tRNA's tertiary structure.
References
{{DEFAULTSORT:D Arm
RNA