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Method for cloning and producing the BssHII restriction endonuclease in E.coli
Method for cloning and producing the BssHII restriction endonuclease in E.coli
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机译:在大肠杆菌中克隆和生产BssHII限制性核酸内切酶的方法
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摘要
The present invention relates to cloning recombinant DNA molecules encoding a multi-specific methylase gene (bssHIIM1), BssHII restriction endonuclease gene (bssHIIR), and the cognate BssHll methylase gene (bssHIIM2) from Bacillus stearothermophilus H3 E. coli. The BssHII multi-specific methylase gene was first cloned in a Sau3Al library using a modified pLITMUS28 vector (New England Biolabs, Inc., Beverly, MA) with two BssHII sites. Expression of the multi-specific BssHll methylase renders the two BssHll sites resistant to BssHll digestion. Surprisingly, the cloned methylase also modifies some other sites in addition to BssHll site (5'GCGCGC3'). The methylase also modifies BsrFI site (5'RCCGGY3') and HaeII site (5'RGCGCY3'); and partially modifies Eagl site (5'CGGCCG3') and MIuI site (5'ACGCGT3'). The beginning of the bssHIIR gene was cloned by using two degenerate primers based on the N-terminal amino acid sequence in PCR. The rest of the bssHIIR gene was cloned by inverse PCR. The cognate bssHIIM2 gene was cloned by inverse PCR and PCR. The BssHll restriction endonuclease gene was expressed in E. coli host ER417 carrying three plasmids pLysP, pLG-BssHIIM2, pET21AT-BssHIIR.
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机译:本发明涉及从嗜热脂肪芽孢杆菌H3大肠杆菌中克隆编码多特异性甲基化酶基因(bssHIIM1),BssHII限制性核酸内切酶基因(bssHIIR)和相关的BssH11甲基化酶基因(bssHIIM2)的重组DNA分子。首先使用具有两个BssHII位点的修饰的pLITMUS28载体(New England Biolabs,Inc.,Beverly,MA)将BssHII多特异性甲基化酶基因克隆到Sau3A1文库中。多特异性BssHll甲基化酶的表达使得两个BssHll位点抵抗BssHll消化。令人惊讶地,除了BssHII位点(5'GCGCGC3'),克隆的甲基化酶还修饰了一些其他位点。甲基化酶还修饰BsrFI位点(5'RCCGGY3')和HaeII位点(5'RGCGCY3');并部分修改了Eagl位点(5'CGGCCG3')和MIuI位点(5'ACGCGT3')。通过使用两个基于PCR中N末端氨基酸序列的简并引物克隆bssHIIR基因的开始。通过反向PCR克隆了其余的bssHIIR基因。通过反向PCR和PCR克隆了同源的bssHIIM2基因。 BssH11限制性核酸内切酶基因在大肠杆菌宿主ER417中表达,携带三个质粒pLysP,pLG-BssHIIM2,pET21AT-BssHIIR。
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