Single strand binding protein
Single strand binding proteins (SSB, single-stranded binding protein ) are proteins involved in DNA binding to the replication to facilitate in which the primer hybridization (engl. Primer annealing , process of the attachment of a primer to DNA sequences) improve. At the same time, these proteins prevent premature hybridization of the already separated complementary strands during DNA replication , which is also referred to as annealing . Furthermore, it protects the single strands from nucleases. They occur in all living things except thermoproteales .
properties
Viral SSBs (including bacteriophage SSBs ) are mostly monomers . Bacterial SSB are often tetramers made up of four identical subunits (19 kDa each). In eukaryotes , SSB occur in the nucleus and are trimers made up of three different units. The following are known in detail in humans:
The SSB bind specifically to single-stranded DNA (single stranded DNA = ss-DNA). A range of approx. 60 nucleotides is covered. The binding is cooperative.
Individual evidence
- ^ AG Kozlov, R. Galletto, TM Lohman: SSB-DNA binding monitored by fluorescence intensity and anisotropy. In: Methods in molecular biology (Clifton, NJ). Volume 922, 2012, pp. 55-83, doi : 10.1007 / 978-1-62703-032-8_4 . PMID 22976177 .
- ↑ PE Pestryakov, OI Lavrik: Mechanisms of single-stranded DNA-binding protein functioning in cellular DNA metabolism. In: Biochemistry. Biokhimii? A. Volume 73, Number 13, December 2008, pp. 1388-1404, PMID 19216707 .
- ^ EA McKinney, MT Oliveira: Replicating animal mitochondrial DNA. In: Genetics and molecular biology. Volume 36, Number 3, September 2013, pp. 308-315, doi : 10.1590 / S1415-47572013000300002 . PMID 24130435 . PMC 3795181 (free full text).