In molecular biology, a guanine tetrad (also known as a G-tetrad or G-quartet) is a structure composed of four guanine bases in a square planar array. [1] [2] They most prominently contribute to the structure of G-quadruplexes, where their hydrogen bonding stabilizes the structure. [3] [4] Usually, there are at least two guanine tetrads in a G-quadruplex, and they often feature Hoogsteen-style hydrogen bonding. [1]
Guanine tetrads are formed by sequences rich in guanine, such as GGGGC. [5] They may also play a role in the dimerization of non-endogenous RNAs to facilitate the replication of some viruses. [5] Guanine tetrads dimerize through their 5' ends since it is more energetically favorable. [6]
They can be stabilized by central cations, such as lithium, sodium, potassium, rubidium, or caesium. [7] [8] However, they still form a variety of different structures. [1] Guanine tetrads are not always stable, but the sugar-phosphate backbone of DNA can assist in stability of the guanine tetrads themselves. [1] Guanine tetrads are more stable when stacked, as intermolecular forces between each layers help stabilize them. [9]
Guanine tetrads can also influence recombination, replication, and transcription. [1] [2] For instance, guanine tetrads are found in the promoter region of the Myc family of oncogenes. [10] They also function in immunoglobulin class switching and may play a role in the genome of HIV. [11] Guanine tetrads appear frequently in the telomeric regions of DNA. [3]
In molecular biology, a guanine tetrad (also known as a G-tetrad or G-quartet) is a structure composed of four guanine bases in a square planar array. [1] [2] They most prominently contribute to the structure of G-quadruplexes, where their hydrogen bonding stabilizes the structure. [3] [4] Usually, there are at least two guanine tetrads in a G-quadruplex, and they often feature Hoogsteen-style hydrogen bonding. [1]
Guanine tetrads are formed by sequences rich in guanine, such as GGGGC. [5] They may also play a role in the dimerization of non-endogenous RNAs to facilitate the replication of some viruses. [5] Guanine tetrads dimerize through their 5' ends since it is more energetically favorable. [6]
They can be stabilized by central cations, such as lithium, sodium, potassium, rubidium, or caesium. [7] [8] However, they still form a variety of different structures. [1] Guanine tetrads are not always stable, but the sugar-phosphate backbone of DNA can assist in stability of the guanine tetrads themselves. [1] Guanine tetrads are more stable when stacked, as intermolecular forces between each layers help stabilize them. [9]
Guanine tetrads can also influence recombination, replication, and transcription. [1] [2] For instance, guanine tetrads are found in the promoter region of the Myc family of oncogenes. [10] They also function in immunoglobulin class switching and may play a role in the genome of HIV. [11] Guanine tetrads appear frequently in the telomeric regions of DNA. [3]