The D arm is a feature in the tertiary structure of transfer RNA (tRNA). It is composed of the two D stems and the D loop. The D loop contains the base dihydrouridine (D), for which the arm is named. [1] The D loop's main function is that of recognition.

Dihydrouridine (abbreviated as D, [1] DHU, or UH 2) is a pyrimidine nucleoside which is the result of adding two hydrogen atoms to a uridine, making it a fully saturated pyrimidine ring with no remaining double bonds.

Acceptor arm. It is formed by the base pairing of 7-9 nucleotides of 5’ terminal and 3’ terminal. The 5’ terminal has a phosphate group and the 3’ ends with a specific sequence of CCA or CCA tail. The amino acid attaches to the 3’ hydroxyl group of the acceptor arm.

Nov 28, 2011 · Dihydrouridine (D) is a highly conserved modified base found in tRNAs from all domains of life. Dihydrouridine synthase (Dus) catalyzes the D formation of tRNA through reduction of uracil base with flavin mononucleotide (FMN) as a cofactor.

D-arm is also known as “Aminoacyl synthetase binding site” as it activates the amino acid synthesis by synthesizing an enzyme (aminoacyl tRNA synthetase). The enzyme promotes the specific and robust binding of amino acid to the tRNA with the help of an ATP molecule.

The last arm of the tRNA is the DHU-arm named after the occurrence of dihydrouridine in all tRNAs. In the early 1970s, the three-dimensional structure of tRNA was determined by X-ray diffraction of tRNA crystals.

Jun 28, 2012 · Dihydrouridine (D; 5,6-dihydro-uridine) is one of the posttranscriptionally modified nucleosides. It is a product of the reduction of uridine (U), and can be further modified to 5-methyldihydrouridine (m5D). D is commonly present in the tRNA from Bacteria, Eukaryota, and some Archaea [1].

The functions of DHU arm is recognition of its proper aminoacyl-tRNA synthetase and TΨC arm is involved in binding of the aminoacyl-tRNA to the ribosomal surface.

DHU arm and a large, base-paired extra arm. These tRNA species have only one pyrimidine before, and two or more after, the constant GG sequence in the DHU loop.

The paired zones define four arms in the structure of tRNA; in sequence from 5' to 3', they are: colour the arms this way. Each arm (except the amino acid acceptor) has a paired region, the stem, and an unpaired one on its end, the loop.