Recombinase A: Difference between revisions
Taylor Light (talk | contribs) No edit summary |
Taylor Light (talk | contribs) No edit summary |
||
| Line 3: | Line 3: | ||
<scene name='41/413118/Reca_adp_mg/3'>RecA with ADP and Mg bound</scene> | <scene name='41/413118/Reca_adp_mg/3'>RecA with ADP and Mg bound</scene> | ||
[[Recombinase A]] (RecA) is a naturally aggregating 352 amino acid | [[Recombinase A]] (RecA) is a naturally aggregating 352 amino acid protein <ref name=Shan> Shan, Q.; Cox, M. M.; Inman, R. B. DNA Strand Exchange Promoted by RecA K72R. J. Biol. Chem. 1996, 271, 5712-5724. DOI:10.1074/jbc.271.10.5712 </ref> involved in DNA repair, is an important asset to the genetic integrity of the ''Escherichia coli'' (''E. coli'') genome. The survival of all species rely on such DNA repair processes. RecA homologues are found in all kingdoms including archaebacteria, eubacteria, and eukaryotes.<ref name=Brendel> Brendel, V.; Brocchieri, L.; Sandler, S.J.; Clark, A.J.; Karlin, S. Evolutionary comparisons of RecA-like proteins across all major kingdoms of living organisms. J. Mol. Evol. 1997, 44, 528-541. DOI: 10.1007/PL00006177 </ref> RAD51, for example, is a RecA homologue found specifically in humans.<ref name=Baumann> Baumann, P.; Benson, F. E.; West, S. C. Human Rad51 Protein Promotes ATP-Dependent Homologous Pairing and Strand Transfer Reactions in Vitro. Cell. 1996, 87, 757-766. DOI: 10.1016/S0092-8674(00)81394-X </ref> An over-expression of RAD51 in the nuclei of tumor cells when compared to those of normal breast tissue has been linked to sporadic, non-hereditary, breast cancers.<ref name=Maacke> Maacke, H.; Opitz, S.; Jost, K.; Hamdorf, W.; Henning, W. Krüger, S. Feller, A.C.; Lopens, A.; Diedrich, K.; Schwinger, E.; Stürzbecher, H.W. Over-expression of wild-type Rad51 correlates with histological grading of invasive ductal breast cancer. Int. J. Cancer. 2000, 88, 907-913. DOI: 10.1002/1097-0215(20001215)88:63.0.CO;2-4 </ref> | ||
== DNA Repair == | == DNA Repair == | ||
| Line 16: | Line 16: | ||
== RecA and Hofmeister Salts == | == RecA and Hofmeister Salts == | ||
High salt concentrations have also been shown to be able to elongate the RecA protein filament as well. Petukhov et al. demonstrated that a high concentration of NaCl increased the helical pitch from 7.8 ± 0.3 to 8.6 ± 0.1 nm.k16 Thus, high salt concentrations appear to induce the active (stretched) form of RecA in the absence of DNA.k16 Other studies have found that the free Magnesium ion binds to RecA and extends the filament more than 150% compared to the filament when DNA is bound.{Lusetti} Moreover, although normally RecA requires DNA to hydrolyze ATP, high salt concentrations are able to stimulate ATP hydrolysis in the absence of DNA.k17 Brenner and Zlotnick reported that the presence of monovalent salts changed the distribution of RecA aggregation states and that the more aggregated structures corresponded to higher protein concentration.T8 Previous studies have shown that various Hofmeister salts affect the secondary structure, stability, and aggregation behavior of RecA differently.T8,T12 Additionally, RecA has been demonstrated to follow the inverse-anionic Hofmeister series and the presence of some ions promotes nonspecific aggregation.T12 | High salt concentrations have also been shown to be able to elongate the RecA protein filament as well. Petukhov et al. demonstrated that a high concentration of NaCl increased the helical pitch from 7.8 ± 0.3 to 8.6 ± 0.1 nm.k16 Thus, high salt concentrations appear to induce the active (stretched) form of RecA in the absence of DNA.k16 Other studies have found that the free Magnesium ion binds to RecA and extends the filament more than 150% compared to the filament when DNA is bound.{Lusetti} Moreover, although normally RecA requires DNA to hydrolyze ATP, high salt concentrations are able to stimulate ATP hydrolysis in the absence of DNA.k17 Brenner and Zlotnick reported that the presence of monovalent salts changed the distribution of RecA aggregation states and that the more aggregated structures corresponded to higher protein concentration.T8 Previous studies have shown that various Hofmeister salts affect the secondary structure, stability, and aggregation behavior of RecA differently.T8,T12 Additionally, RecA has been demonstrated to follow the inverse-anionic Hofmeister series and the presence of some ions promotes nonspecific aggregation.T12 | ||
== References == | |||
<references/> | |||
--[[User:Taylor Light|Taylor Light]] 22:30, 25 February 2015 (IST) | --[[User:Taylor Light|Taylor Light]] 22:30, 25 February 2015 (IST) | ||