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Holliday junction resolution: RuvC |
Резольваза - фермент, разрешающий узлы в структурах Холлидея; при его yчастии образуются липкие концы, соединяемые лигазой.
Основная резольваза у E. coli – RuvC
Ruv C dimer
Holliday junction resolution by RuvC protein. The continuous strands of the stacked-X structure (a) which form the wide angles in the unfolded RuvC-junction complex (b) are indicated by asterisks. The sites of incision are indicated by scissors. The products of resolution (c) can be repaired by DNA ligase.
West SC. Processing of recombination intermediates by the RuvABC proteins. Annu Rev Genet. 1997;31:213-44. doi: 10.1146/annurev.genet.31.1.213. PMID: 9442895.
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Holliday junction resolution: RusC |
Резольваза - фермент, разрешающий узлы в структурах Холлидея; при его yчастии образуются липкие концы, соединяемые лигазой.
RusA – резольваза E. coli
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b |
T7 ENDO I RESOLVASE
T7 ENDO I
RESOLVASE
Model of RusA in complex with a DNA HJ. (a) View down the 2-fold axis of the protein dimer with the locations of the DNA scissile bonds and catalytically critical residues marked with orange and pink spheres, respectively, and the cytidines from the CC dinucleotide sequence recognized during sequence specific cleavage highlighted in green (unpaired base) and cyan. The partner guanosine of the unpaired base is also shown in green. (b) View perpendicular to that in (a).
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САЙТ-СПЕЦИФИЧЕСКАЯ РЕКОМБИНАЦИЯ |
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Интеграция кольцевой ДНК фага в хромосому |
Нуклеотидные последовательности |
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E. coli. Для встраивания необходимы интеграза |
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attP и attB сайтов |
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(Int), кодируемая фаговым геномом и |
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бактериальный белок IHF. В выщеплении |
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принимает участие еще один фаговый белок Xis. |
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САЙТ-СПЕЦИФИЧЕСКИЕ РЕКОМБИНАЗЫ |
Traditional view
Current view
Tyr-Recombinases: Details of the crossover step
https://en.wikipedia.org/wiki/Site-specific_recombination
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САЙТ-СПЕЦИФИЧЕСКИЕ РЕКОМБИНАЗЫ
Ser-Recombinases: The (essentially irreversible) subunit-rotation pathway.
https://en.wikipedia.org/wiki/Site-specific_recombination
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САЙТ-СПЕЦИФИЧЕСКИЕ РЕКОМБИНАЗЫ |
λ Integrase (tyrosine recombinase family) and the overlapping ensembles of protein binding sites that comprise att site DNA
Landy A. The λ Integrase Site-specific Recombination Pathway. Microbiol Spectr. 2015 Apr;3(2):MDNA3- 0051-2014. doi: 10.1128/microbiolspec.MDNA3-0051-2014. PMID: 26104711; PMCID: PMC5710010.
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САЙТ-СПЕЦИФИЧЕСКИЕ РЕКОМБИНАЗЫ |
Formation, resolution, and trapping of Holliday junctions (HJ). (A) The top strand of each att site is cleaved via formation of a high-energy phosphotyrosine intermediate and the strands are exchanged (three bases are “swapped”) to form the HJ, thus, creating a branch point close to the center of the overlap regions.
A conformational change of the complex that slightly repositions the branch point and more extremely repositions the Int protomers leads to the second swap of DNA strands and resolution of the HJ to helical products. These features of the reaction suggested the mechanism-based method of trapping HJ complexes shown in (B). The left panel shows the DNA sequence changes made in the 7 bp overlap regions to trap HJ intermediates (lower case letters). Following the first pair of Int cleavages (via the active site Tyr) on one side of the overlap regions (arranged here in antiparallel orientation), the “top” strands are swapped to form the
HJ; this simultaneously converts the unpaired (bubble) bases to duplex DNA. On the other side, the sequence differences between the two overlap regions strongly disfavor the second (“bottom”) strand swap that would resolve the HJ, because this would generate unpaired bubbles in the product complex. This diagram applies to both integrative and excisive recombination (even though the labels refer to integrative recombination).
Plaques of Lambda Phages on E. coli XL1-Blue MRF'
Генетическая рекомбинация и формирование антител
V(D)J-рекомбинация (V(D)J-реаранжировка) — механизм соматической рекомбинации ДНК, происходящий на ранних этапах дифференцировки лимфоцитов и приводящий к формированию антиген-распознающих участков антител и Т-клеточного рецептора.
Вариабельный
домен
Константные
домены
Организация генов иммуноглобулинов в геноме человека
https://ru.wikipedia.org/wiki/V(D)J-рекомбинация
Генетическая рекомбинация и формирование антител
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Сигнальные |
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последовательности — |
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recombination signal |
Упрощённая схема V(D)J-рекомбинации |
sequence (RSS) |