Queuosine is a modified
nucleoside
Nucleosides are glycosylamines that can be thought of as nucleotides without a phosphate group. A nucleoside consists simply of a nucleobase (also termed a nitrogenous base) and a five-carbon sugar (ribose or 2'-deoxyribose) whereas a nucleotid ...
that is present in certain
tRNA
Transfer ribonucleic acid (tRNA), formerly referred to as soluble ribonucleic acid (sRNA), is an adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length (in eukaryotes). In a cell, it provides the physical link between the gene ...
s in
bacteria
Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...
and
eukaryotes
The eukaryotes ( ) constitute the domain of Eukaryota or Eukarya, organisms whose cells have a membrane-bound nucleus. All animals, plants, fungi, seaweeds, and many unicellular organisms are eukaryotes. They constitute a major group of ...
. It contains the
nucleobase
Nucleotide bases (also nucleobases, nitrogenous bases) are nitrogen-containing biological compounds that form nucleosides, which, in turn, are components of nucleotides, with all of these monomers constituting the basic building blocks of nuc ...
queuine. Originally identified in ''
E. coli
''Escherichia coli'' ( )Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. is a gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus ''Escherichia'' that is commonly foun ...
'', queuosine was found to occupy the first anticodon position of tRNAs for
histidine
Histidine (symbol His or H) is an essential amino acid that is used in the biosynthesis of proteins. It contains an Amine, α-amino group (which is in the protonated –NH3+ form under Physiological condition, biological conditions), a carboxylic ...
,
aspartic acid
Aspartic acid (symbol Asp or D; the ionic form is known as aspartate), is an α-amino acid that is used in the biosynthesis of proteins. The L-isomer of aspartic acid is one of the 22 proteinogenic amino acids, i.e., the building blocks of protei ...
,
asparagine
Asparagine (symbol Asn or N) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH form under biological conditions), an α-carboxylic acid group (which is in the depro ...
and
tyrosine
-Tyrosine or tyrosine (symbol Tyr or Y) or 4-hydroxyphenylalanine is one of the 20 standard amino acids that are used by cells to synthesize proteins. It is a conditionally essential amino acid with a polar side group. The word "tyrosine" is ...
. The first anticodon position pairs with the third "
wobble
Wobble or wobbles may refer to:
* "Wobble" (song), a single by V.I.C.
* "Wobble", a song by Flo Rida from his 2015 EP '' My House''
* ''Wobble'' (album), an album by Black Market Karma
* Wobbles (equine disorder), a disorder of the nervous syst ...
" position in codons, and queuosine improves accuracy of
translation
Translation is the communication of the semantics, meaning of a #Source and target languages, source-language text by means of an Dynamic and formal equivalence, equivalent #Source and target languages, target-language text. The English la ...
compared to
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 monophosp ...
. Synthesis of queuosine begins with
GTP. In bacteria, three structurally unrelated classes of
riboswitch
In molecular biology, a riboswitch is a regulatory segment of a messenger RNA molecule that binds a small molecule, resulting in a change in Translation (biology), production of the proteins encoded by the mRNA. Thus, an mRNA that contains a ribo ...
are known to regulate
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
s that are involved in the synthesis or transport of pre-queuosine
1, a precursor to queuosine:
PreQ1-I riboswitches,
PreQ1-II riboswitches and
PreQ1-III riboswitches.
Queuosine biosynthesis genes have also been found on phage genomes and may be involved in protection from genome degradation by the host.
References
Further reading
*
{{refend
External links
* Wikigenes
Queuosine* Human Metabolome Database
Queuosine (HMDB11596)
Nucleosides
Pyrrolopyrimidines
Tetrahydrofurans
Cyclopentenes
Hydroxymethyl compounds