Tetraloop
Encyclopedia
Tetraloops are a type of four-base hairpin loop motif
s in RNA secondary structure
that cap many double helices. Three types of tetraloops are common in ribosomal RNA
: GNRA, UNCG and CUUG. The GNRA tetraloop has a guanine
-adenine
base-pair where the guanine is 5' to the helix and the adenine is 3' to the helix.
Structural motif
In a chain-like biological molecule, such as a protein or nucleic acid, a structural motif is a supersecondary structure, which appears also in a variety of other molecules...
s in RNA secondary structure
Nucleic acid secondary structure
The secondary structure of a nucleic acid molecule refers to the basepairing interactions within a single molecule or set of interacting molecules, and can be represented as a list of bases which are paired in a nucleic acid molecule....
that cap many double helices. Three types of tetraloops are common in ribosomal RNA
Ribosomal RNA
Ribosomal ribonucleic acid is the RNA component of the ribosome, the enzyme that is the site of protein synthesis in all living cells. Ribosomal RNA provides a mechanism for decoding mRNA into amino acids and interacts with tRNAs during translation by providing peptidyl transferase activity...
: GNRA, UNCG and CUUG. The GNRA tetraloop has a guanine
Guanine
Guanine is one of the four main nucleobases found in the nucleic acids DNA and RNA, the others being adenine, cytosine, and thymine . In DNA, guanine is paired with cytosine. With the formula C5H5N5O, guanine is a derivative of purine, consisting of a fused pyrimidine-imidazole ring system with...
-adenine
Adenine
Adenine is a nucleobase with a variety of roles in biochemistry including cellular respiration, in the form of both the energy-rich adenosine triphosphate and the cofactors nicotinamide adenine dinucleotide and flavin adenine dinucleotide , and protein synthesis, as a chemical component of DNA...
base-pair where the guanine is 5' to the helix and the adenine is 3' to the helix.
See also
- RNA Tertiary Structure (section Tetraloop-receptor interactions)