Charles A D, Gautier A E, Edge M D, Knowles J R
J Biol Chem. 1982 Jul 25;257(14):7930-2.
A method has been developed for constructing site-specific mutations by using a strongly selectable marker on which to "piggy-back" a desired mutation that may be phenotypically silent. Using this approach, a new unique Eco RI restriction site has been generated at the beginning of the signal codons of the beta-lactamase gene of the plasmid pBR322. The consequential alteration of the second amino acid of the signal from Ser to Arg has no effect on either the transport or the processing of the beta-lactamase.
已开发出一种方法，通过使用一个强选择标记来构建位点特异性突变，在该标记上“搭载”一个可能在表型上无明显变化的所需突变。利用这种方法，在质粒pBR322的β-内酰胺酶基因信号密码子起始处产生了一个新的独特的Eco RI限制性酶切位点。信号序列第二个氨基酸从丝氨酸变为精氨酸的相应改变对β-内酰胺酶的转运或加工均无影响。
