Roles of two large serine recombinases in mobilizing the methicillin-resistance cassette SCCmec.
Roles of two large serine recombinases in mobilizing the methicillin-resistance cassette SCCmec.
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DOI：
10.1111/mmi.12253
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发表时间：
2013-06
影响因子：
3.6
通讯作者：
Rice PA
中科院分区：
文献类型：
--
作者：
Misiura A;Pigli YZ;Boyle-Vavra S;Daum RS;Boocock MR;Rice PA
耐甲氧西林金黄色葡萄球菌（MRSA）是通过获得一个移动的元件--葡萄球菌盒式染色体mec（SCCmec）而产生的。SCCmec的整合和切除是由一个不寻常的位点特异性重组系统介导的。SCCmec的大多数变体编码两种重组酶，CcrA和CcrB，它们属于大丝氨酸家族。由于CcrA和CcrB总是在一起，我们试图解决他们的具体作用。我们发现CcrA和CcrB在大肠杆菌中既可以进行切除重组，也可以进行整合重组。在没有任何宿主特异性或SCCmec编码的辅因子的情况下，CcrA和CcrB在其底物选择上是混杂的：它们除了作用于典型的重组位点之外还作用于许多非典型的重组位点对，这可以解释串联插入到SCCmec附着位点中。此外，CcrB始终是必需的，但CcrA仅在四个半位点之一存在时才是必需的。转录活性与DNA结合相关：CcrA仅识别与宿主染色体上保守编码框架重叠的半个位点。因此，我们建议，CcrA作为一个特异性因子，出现通过模块化进化，使识别的细菌重组位点，不是一个反向重复。
Methicillin-resistant Staphylococcus aureus (MRSA) emerged via acquisition of a mobile element, staphylococcal cassette chromosome mec (SCCmec). Integration and excision of SCCmec is mediated by an unusual site-specific recombination system. Most variants of SCCmec encode two recombinases, CcrA and CcrB, that belong to the large serine family. Since CcrA and CcrB are always found together, we sought to address their specific roles. We show here that CcrA and CcrB can carry out both excisive and integrative recombination in E. coli in the absence of any host-specific or SCCmec-encoded cofactors. CcrA and CcrB are promiscuous in their substrate choice: they act on many non-canonical pairs of recombination sites in addition to the canonical ones, which may explain tandem insertions into the SCCmec attachment site. Moreover, CcrB is always required, but CcrA is only required if one of the four half sites is present. Recombinational activity correlates with DNA-binding: CcrA recognizes only that half site, which overlaps a conserved coding frame on the host chromosome. Therefore, we propose that CcrA serves as a specificity factor that emerged through modular evolution to enable recognition of a bacterial recombination site that is not an inverted repeat.
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影响因子：
4.9
作者：
HARTMAN, B;TOMASZ, A
通讯作者：
TOMASZ, A
影响因子：
16
作者：
Ghosh, P;Kim, AI;Hatfull, GF
通讯作者：
Hatfull, GF
DOI：
10.1073/pnas.090527097
发表时间：
2000-05-23
影响因子：
11.1
作者：
Groth, AC;Olivares, EC;Calos, MP
通讯作者：
Calos, MP
影响因子：
3.6
作者：
Burke, ME;Arnold, PH;Stark, WM
通讯作者：
Stark, WM
影响因子：
4.9
作者：
Katayama, Y;Ito, T;Hiramatsu, K
通讯作者：
Hiramatsu, K