Difference between revisions of "Cytosine" - New World Encyclopedia
Rick Swarts (talk | contribs) |
Rick Swarts (talk | contribs) |
||
| Line 6: | Line 6: | ||
! colspan="2" align=center bgcolor="#cccccc" | '''Cytosine''' | ! colspan="2" align=center bgcolor="#cccccc" | '''Cytosine''' | ||
|- | |- | ||
| − | | [[IUPAC nomenclature|Chemical name]] | + | | [[IUPAC nomenclature|Chemical name]]* |
| 4-Aminopyrimidin-2(1''H'')-one | | 4-Aminopyrimidin-2(1''H'')-one | ||
|- | |- | ||
| − | | [[Chemical formula]] | + | | [[Chemical formula]]* |
| C<sub>4</sub>H<sub>5</sub>N<sub>3</sub>O | | C<sub>4</sub>H<sub>5</sub>N<sub>3</sub>O | ||
|- | |- | ||
| − | | [[Molecular mass]] | + | | [[Molecular mass]]* |
| 111.102 g/mol | | 111.102 g/mol | ||
|- | |- | ||
| − | | [[Melting point]] | + | | [[Melting point]]* |
| 320 - 325°C (decomp) | | 320 - 325°C (decomp) | ||
|- | |- | ||
| − | | [[CAS registry number|CAS number]] | + | | [[CAS registry number|CAS number]]* |
| 71-30-7 | | 71-30-7 | ||
|- | |- | ||
| − | | [[Simplified molecular input line entry specification|SMILES]] | + | | [[Simplified molecular input line entry specification|SMILES]]* |
| NC1=NC(NC=C1)=O | | NC1=NC(NC=C1)=O | ||
|- | |- | ||
| Line 30: | Line 30: | ||
'''Cytosine''' is one of the 5 main [[nucleotide#Chemical structure and nomenclature|nucleobase]]s used in storing and transporting [[genetics|genetic]] information within a cell in the [[nucleic acid]]s [[DNA]] and [[RNA]]. The other four nucleobases are [[adenine]], [[guanine]], [[thymine]], and [[uracil]]. Cytosine, thymine, and uracil are [[pyrimidine]] derivatives, while guanine and adenine are [[purine]] derivatives. The [[nucleotide#Chemical structure and nomenclature|nucleoside]] of cytosine is [[cytidine]]. | '''Cytosine''' is one of the 5 main [[nucleotide#Chemical structure and nomenclature|nucleobase]]s used in storing and transporting [[genetics|genetic]] information within a cell in the [[nucleic acid]]s [[DNA]] and [[RNA]]. The other four nucleobases are [[adenine]], [[guanine]], [[thymine]], and [[uracil]]. Cytosine, thymine, and uracil are [[pyrimidine]] derivatives, while guanine and adenine are [[purine]] derivatives. The [[nucleotide#Chemical structure and nomenclature|nucleoside]] of cytosine is [[cytidine]]. | ||
| − | In DNA, cytosine and thymine form hydrogen bonds with their complementary purine derivatives, guanine and adenine. In RNA, the complement of adenine is uracil instead of thymine. Thus, cytosine, along with adenine and guanine, is present in both DNA and RNA, whereas thymine is usually seen only in DNA and uracil only in RNA. | + | In DNA, cytosine (C) and thymine (T) form hydrogen bonds with their complementary purine derivatives, guanine (G) and adenine (A). In RNA, the complement of adenine is uracil (U)instead of thymine. Thus, cytosine, along with adenine and guanine, is present in both DNA and RNA, whereas thymine is usually seen only in DNA and uracil only in RNA. |
In Watson-Crick base pairing, cytosine forms three hydrogen bonds with guanine. From the point of view of structure, it is remarkable that cytosine, with its three binding sites, only attaches to guanine in DNA, while adenine, with two sites for hydrogen binding, only attaches to thymine. The way these hydrogen bonds hold the strands of the nucleic acid together to form the double helix, yet allowing the strands to "unzip" for replication and transcription, is simply amazing from a design point of view. | In Watson-Crick base pairing, cytosine forms three hydrogen bonds with guanine. From the point of view of structure, it is remarkable that cytosine, with its three binding sites, only attaches to guanine in DNA, while adenine, with two sites for hydrogen binding, only attaches to thymine. The way these hydrogen bonds hold the strands of the nucleic acid together to form the double helix, yet allowing the strands to "unzip" for replication and transcription, is simply amazing from a design point of view. | ||
| − | Cytosine can also be a part of a [[nucleotide]]. As cytidine triphosphate (CTP), it can act as a co-factor to [[enzyme]]s, and can transfer a phosphate to convert adenosine diphosphate (ADP) to [[adenosine triphosphate]] (ATP). | + | Cytosine can also be a part of a [[nucleotide]] other than related to DNA or RNA. As cytidine triphosphate (CTP), it can act as a co-factor to [[enzyme]]s, and can transfer a phosphate to convert adenosine diphosphate (ADP) to [[adenosine triphosphate]] (ATP). |
| − | |||
==Properties== | ==Properties== | ||
Cytosine is a [[pyrimidine]] derivative, with a heterocyclic, aromatic ring, and two substituents attached (an amine group at position 4 and a keto group at position 2). | Cytosine is a [[pyrimidine]] derivative, with a heterocyclic, aromatic ring, and two substituents attached (an amine group at position 4 and a keto group at position 2). | ||
| − | ''Heterocyclic'' compounds are organic compounds (those containing [[carbon]]) that contain a ring structure containing atoms in addition to carbon, such as [[sulfur]], [[oxygen]], or [[nitrogen]], as part of the ring. ''Aromaticity'' is a chemical property in which a conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibit a stabilization stronger than would be expected by the stabilization of conjugation alone. | + | ''Heterocyclic'' compounds are organic compounds (those containing [[carbon]]) that contain a ring structure containing atoms in addition to carbon, such as [[sulfur]], [[oxygen]], or [[nitrogen]], as part of the ring. ''Aromaticity'' is a chemical property in which a conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibit a stabilization stronger than would be expected by the stabilization of conjugation alone. In organic chemistry, a ''substituent'' is an atom or group of atoms substituted in place of a hydrogen atom on the parent chain of a hydrocarbon. |
| − | |||
| − | |||
| − | In | ||
| − | + | In DNA and RNA, cytosine is paired with [[guanine]]. However, it is inherently unstable, and can change into [[uracil]] (spontaneous deamination). This can lead to a point [[mutation]] if not repaired by the DNA repair [[enzymes]], such as uracil glycosylase, which cleaves a uracil in DNA. | |
| + | Cytosine can also be methylated into 5-methylcytosine by an enzyme called DNA methyltransferase. | ||
| + | [[Image:DNAbasePairing2.png|thumb|500px|center|Chemical structure of base pair bonding. Thymine (T) bonds with adenine (A), and cytosine (C) bonds with guanine (G).]] | ||
| + | ==History and uses== | ||
Cytosine was first discovered in 1894 when it was isolated from calf [[thymus]] tissues. A structure was proposed in 1903, and was synthesized (and thus confirmed) in the laboratory in the same year. | Cytosine was first discovered in 1894 when it was isolated from calf [[thymus]] tissues. A structure was proposed in 1903, and was synthesized (and thus confirmed) in the laboratory in the same year. | ||
| − | Cytosine recently found use in | + | Cytosine recently found use in quantum computation. The first time any |
| − | + | quantum mechanical properties were harnessed to process information | |
| − | took place on August 1st in 1998 when researchers at Oxford implemented | + | took place on August 1st in 1998 when researchers at Oxford implemented David Deutsch's algorithm on a two qubit NMRQC (Nuclear Magnetic Resonance Quantum Computer) based on the cytosine molecule. |
| + | ==References== | ||
| + | * Bernardi, G., B. Olofsson, J. Filipski, M. Zerial, J. Salinas, et al. 1985. The mosaic genome of warm-blooded vertebrates. ''Science'' 228: 953–958. | ||
| + | * Smith, N. G., and A. Eyre-Walker. 2001. Synonymous codon bias is not caused by mutation bias in G + C-rich genes in humans. ''Mol Biol Evol'' 18: 982–986. | ||
| + | * Vinogradov, A. E. 2003. DNA helix: The importance of being GC-rich. ''Nucleic Acids Res'' 31: 1838–1844. | ||
==External links== | ==External links== | ||
| − | + | ||
| − | |||
| − | |||
| − | |||
*[http://www.pnas.org/cgi/content/full/96/8/4396 Prebiotic cytosine synthesis: A critical analysis and implications for the origin of life] | *[http://www.pnas.org/cgi/content/full/96/8/4396 Prebiotic cytosine synthesis: A critical analysis and implications for the origin of life] | ||
| Line 68: | Line 68: | ||
[[Category:Life sciences]] | [[Category:Life sciences]] | ||
| − | {{ | + | {{credit4|Cytosine|95523605|Heterocyclic_compound|93187808|Aromaticity|93907113|Substituent|90749409}} |
Revision as of 00:19, 31 December 2006
| Cytosine | |
|---|---|
| Chemical name | 4-Aminopyrimidin-2(1H)-one |
| Chemical formula | C4H5N3O |
| Molecular mass | 111.102 g/mol |
| Melting point | 320 - 325°C (decomp) |
| CAS number | 71-30-7 |
| SMILES | NC1=NC(NC=C1)=O |
| |
Cytosine is one of the 5 main nucleobases used in storing and transporting genetic information within a cell in the nucleic acids DNA and RNA. The other four nucleobases are adenine, guanine, thymine, and uracil. Cytosine, thymine, and uracil are pyrimidine derivatives, while guanine and adenine are purine derivatives. The nucleoside of cytosine is cytidine.
In DNA, cytosine (C) and thymine (T) form hydrogen bonds with their complementary purine derivatives, guanine (G) and adenine (A). In RNA, the complement of adenine is uracil (U)instead of thymine. Thus, cytosine, along with adenine and guanine, is present in both DNA and RNA, whereas thymine is usually seen only in DNA and uracil only in RNA.
In Watson-Crick base pairing, cytosine forms three hydrogen bonds with guanine. From the point of view of structure, it is remarkable that cytosine, with its three binding sites, only attaches to guanine in DNA, while adenine, with two sites for hydrogen binding, only attaches to thymine. The way these hydrogen bonds hold the strands of the nucleic acid together to form the double helix, yet allowing the strands to "unzip" for replication and transcription, is simply amazing from a design point of view.
Cytosine can also be a part of a nucleotide other than related to DNA or RNA. As cytidine triphosphate (CTP), it can act as a co-factor to enzymes, and can transfer a phosphate to convert adenosine diphosphate (ADP) to adenosine triphosphate (ATP).
Properties
Cytosine is a pyrimidine derivative, with a heterocyclic, aromatic ring, and two substituents attached (an amine group at position 4 and a keto group at position 2). Heterocyclic compounds are organic compounds (those containing carbon) that contain a ring structure containing atoms in addition to carbon, such as sulfur, oxygen, or nitrogen, as part of the ring. Aromaticity is a chemical property in which a conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibit a stabilization stronger than would be expected by the stabilization of conjugation alone. In organic chemistry, a substituent is an atom or group of atoms substituted in place of a hydrogen atom on the parent chain of a hydrocarbon.
In DNA and RNA, cytosine is paired with guanine. However, it is inherently unstable, and can change into uracil (spontaneous deamination). This can lead to a point mutation if not repaired by the DNA repair enzymes, such as uracil glycosylase, which cleaves a uracil in DNA.
Cytosine can also be methylated into 5-methylcytosine by an enzyme called DNA methyltransferase.
History and uses
Cytosine was first discovered in 1894 when it was isolated from calf thymus tissues. A structure was proposed in 1903, and was synthesized (and thus confirmed) in the laboratory in the same year.
Cytosine recently found use in quantum computation. The first time any quantum mechanical properties were harnessed to process information took place on August 1st in 1998 when researchers at Oxford implemented David Deutsch's algorithm on a two qubit NMRQC (Nuclear Magnetic Resonance Quantum Computer) based on the cytosine molecule.
ReferencesISBN links support NWE through referral fees
- Bernardi, G., B. Olofsson, J. Filipski, M. Zerial, J. Salinas, et al. 1985. The mosaic genome of warm-blooded vertebrates. Science 228: 953–958.
- Smith, N. G., and A. Eyre-Walker. 2001. Synonymous codon bias is not caused by mutation bias in G + C-rich genes in humans. Mol Biol Evol 18: 982–986.
- Vinogradov, A. E. 2003. DNA helix: The importance of being GC-rich. Nucleic Acids Res 31: 1838–1844.
External links
| Nucleic acids edit |
|---|
| Nucleobases: Adenine - Thymine - Uracil - Guanine - Cytosine - Purine - Pyrimidine |
| Nucleosides: Adenosine - Uridine - Guanosine - Cytidine - Deoxyadenosine - Thymidine - Deoxyguanosine - Deoxycytidine |
| Nucleotides: AMP - UMP - GMP - CMP - ADP - UDP - GDP - CDP - ATP - UTP - GTP - CTP - cAMP - cGMP |
| Deoxynucleotides: dAMP - dTMP - dUMP - dGMP - dCMP - dADP - dTDP - dUDP - dGDP - dCDP - dATP - dTTP - dUTP - dGTP - dCTP |
| Nucleic acids: DNA - RNA - LNA - PNA - mRNA - ncRNA - miRNA - rRNA - siRNA - tRNA - mtDNA - Oligonucleotide |
Credits
New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia standards. This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here:
The history of this article since it was imported to New World Encyclopedia:
Note: Some restrictions may apply to use of individual images which are separately licensed.
