DNA-binding proteins

Structural proteins that bind DNA, well-understood examples of non-specific DNA-protein interactions. Within chromosomes, DNA is held in complexes with structural proteins. These proteins organize the DNA into a compact structure called chromatin. The formation of DNA from eukaryotes histone small basic proteins plays an important role; types of proteins in prokaryotes binds to DNA. [63] [64] The histones, nucleosomes forms a complex from a disk-shaped, double-stranded DNA wrapped it revolves around two times. Basic residues in the sugar-phosphate backbone of DNA with histones making ionic bonds to the acidic phosphates, non-specific interactions are formed, largely independent of the base sequence. [65] Chemical modifications of these basic amino acids, methylation, phosphorylation and acetylation considered. [66 ] The chemical shifts of the DNA with histones of the interaction between the DNA more accessible to transcription factors and transcription rate varies. [67] Other non-specific DNA-binding proteins in chromatin moving group in the high proteins (Ing. high- mobility group proteins) binds to DNA bent or distorted. [68] These proteins oluşturarlar bending arrays of nucleosomes and chromosomes give rise to larger-scale structures. [69]
A distinct set of protein of DNA-binding proteins, single-stranded DNA-binding proteins (these are also known as single-stranded DNA binding protein). In humans, replication protein A best understood member of this family of proteins, these proteins double helix is ​​separated cases, including DNA replication, recombination and DNA repair functions. [70] These proteins makes stable single-stranded DNA, its stem-loop ( stem-loop) to generate or are being degraded by nucleases.


Lambda repressor form attached to the DNA target sequence. [71]
Unlike the aforesaid proteins with other proteins evolved to bind specific DNA sequences. The best studied of these transcription factors, proteins that regulate transcription bular. Each transcription factor is connected to a particular set of DNA sequences and activates or inhibits the transcription of genes that sequences close protörleri. Transcription factors do this in two ways. First, bind the RNA polymerase responsible for transcription, either directly or through other mediator proteins that, as a result, would polymerase locates the promoter and transcription start is possible. [72] Another way is to change the histones at the promoter transcription factors bind enzymes that a result of which access to DNA polymerase changes. [73]
It can be found on each side of the DNA binding sequences of the genome of an organism to changes in the activity of a transcription factor can affect thousands of genes. [74] Therefore, these proteins are often environmental changes associated with the processes that control cellular differentiation and development targets of the signal transduction processes. Specificity of this transcription factor interactions with DNA, DNA bases contacts to the edges, so that the DNA sequence of these proteins to "read". Most of the bases of these interactions, it is easily accessible from the major groove bases comes the challenge. [75]