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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. The guanine nucleoside is called guanosine.
Adenine is a nucleobase. It is one of the four nucleobases in the nucleic acid of DNA that are represented by the letters G–C–A–T. The three others are guanine, cytosine and thymine. Its derivatives have a variety of roles in biochemistry including cellular respiration, in the form of both the energy-rich adenosine triphosphate (ATP) and the cofactors nicotinamide adenine dinucleotide (NAD) and flavin adenine dinucleotide (FAD). It also has functions in protein synthesis and as a chemical component of DNA and RNA. The shape of adenine is complementary to either thymine in DNA or uracil in RNA.
Uracil is one of the four nucleobases in the nucleic acid of RNA that are represented by the letters A, G, C and U. The others are adenine (A), cytosine (C), and guanine (G). In RNA, uracil binds to adenine via two hydrogen bonds. In DNA, the uracil nucleobase is replaced by thymine. Uracil is a demethylated form of thymine.
Hypoxanthine is a naturally occurring purine derivative. It is occasionally found as a constituent of nucleic acids, where it is present in the anticodon of tRNA in the form of its nucleoside inosine. It has a tautomer known as 6-hydroxypurine. Hypoxanthine is a necessary additive in certain cell, bacteria, and parasite cultures as a substrate and nitrogen source. For example, it is commonly a required reagent in malaria parasite cultures, since Plasmodium falciparum requires a source of hypoxanthine for nucleic acid synthesis and energy metabolism.
A nitrogenous base, or nitrogen-containing base, is an organic molecule with a nitrogen atom that has the chemical properties of a base. The main biological function of a nitrogenous base is to bond nucleic acids together. A nitrogenous base owes its basic properties to the lone pair of electrons of a nitrogen atom.
Stem-loop intramolecular base pairing is a pattern that can occur in single-stranded DNA or, more commonly, in RNA. The structure is also known as a hairpin or hairpin loop. It occurs when two regions of the same strand, usually complementary in nucleotide sequence when read in opposite directions, base-pair to form a double helix that ends in an unpaired loop. The resulting structure is a key building block of many RNA secondary structures. As an important secondary structure of RNA, it can direct RNA folding, protect structural stability for messenger RNA (mRNA), provide recognition sites for RNA binding proteins, and serve as a substrate for enzymatic reactions.
In enzymology, a rRNA (adenine-N6-)-methyltransferase (EC 2.1.1.48) is an enzyme that catalyzes the chemical reaction
In enzymology, a tRNA (adenine-N1-)-methyltransferase (EC 2.1.1.36) is an enzyme that catalyzes the chemical reaction
In enzymology, a tRNA (adenine-N6-)-methyltransferase (EC 2.1.1.55) is an enzyme that catalyzes the chemical reaction
16S rRNA (adenine1408-N1)-methyltransferase (EC 2.1.1.180, kanamycin-apramycin resistance methylase, 16S rRNA:m1A1408 methyltransferase, KamB, NpmA, 16S rRNA m1A1408 methyltransferase) is an enzyme with systematic name S-adenosyl-L-methionine:16S rRNA (adenine1408-N1)-methyltransferase. This enzyme catalyses the following chemical reaction
23S rRNA (adenine1618-N6)-methyltransferase (EC 2.1.1.181, rRNA large subunit methyltransferase F, YbiN protein, rlmF (gene), m6A1618 methyltransferase) is an enzyme with systematic name S-adenosyl-L-methionine:23S rRNA (adenine1618-N6)-methyltransferase. This enzyme catalyses the following chemical reaction
16S rRNA (adenine1518-N6/adenine1519-N6)-dimethyltransferase (EC 2.1.1.182, S-adenosylmethionine-6-N',N'-adenosyl (rRNA) dimethyltransferase, KsgA, ksgA methyltransferase) is an enzyme with systematic name S-adenosyl-L-methionine:16S rRNA (adenine1518-N6/adenine1519-N6)-dimethyltransferase. This enzyme catalyses the following chemical reaction
23S rRNA (adenine2085-N6)-dimethyltransferase (EC 2.1.1.184, ErmC' methyltransferase, ermC methylase, ermC 23S rRNA methyltransferase, rRNA:m6A methyltransferase ErmC', ErmC', rRNA methyltransferase ErmC' ) is an enzyme with systematic name S-adenosyl-L-methionine:23S rRNA (adenine2085-N6)-dimethyltransferase. This enzyme catalyses the following chemical reaction
23S rRNA (adenine2503-C2)-methyltransferase (EC 2.1.1.192, RlmN, YfgB, Cfr) is an enzyme with systematic name S-adenosyl-L-methionine:23S rRNA (adenine2503-C2)-methyltransferase. This enzyme catalyses the following chemical reaction
TRNA (adenine22-N1)-methyltransferase (EC 2.1.1.217, TrmK, YqfN, Sp1610 (gene), tRNA: m1A22 methyltransferase) is an enzyme with systematic name S-adenosyl-L-methionine:tRNA (adenine22-N1)-methyltransferase. This enzyme catalyses the following chemical reaction
TRNA (adenine9-N1)-methyltransferase (EC 2.1.1.218, Trm10p, tRNA(m1G9/m1A9)-methyltransferase, tRNA(m1G9/m1A9)MTase, TK0422p (gene), tRNA m1A9-methyltransferase, tRNA m1A9 Mtase) is an enzyme with systematic name S-adenosyl-L-methionine:tRNA (adenine9-N1)-methyltransferase. This enzyme catalyses the following chemical reaction
TRNA (adenine57-N1/adenine58-N1)-methyltransferase (EC 2.1.1.219, TrmI, PabTrmI, AqTrmI, MtTrmI) is an enzyme with systematic name S-adenosyl-L-methionine:tRNA (adenine57/adenine58-N1)-methyltransferase. This enzyme catalyses the following chemical reaction:
TRNA (adenine58-N1)-methyltransferase (EC 2.1.1.220, tRNA m1A58 methyltransferase, tRNA (m1A58) methyltransferase, TrmI, tRNA (m1A58) Mtase, Rv2118cp, Gcd10p-Gcd14p, Trm61p-Trm6p) is an enzyme with systematic name S-adenosyl-L-methionine:tRNA (adenine58-N1)-methyltransferase. This enzyme catalyses the following chemical reaction
TRNA1Val (adenine37-N6)-methyltransferase (EC 2.1.1.223, YfiC) is an enzyme with systematic name S-adenosyl-L-methionine:tRNA1Val (adenine37-N6)-methyltransferase. This enzyme catalyses the following chemical reaction
