title: An easy-to-use site-directed mutagenesis method with a designed restriction site for convenient and reliable mutant screening.
abstract: Site-directed mutagenesis (SDM) has been a very important method to probe the function-structure relationship of proteins. In this study, we introduced an easy-to-use, polymerase chain reaction (PCR)-based SDM method for double-stranded plasmid DNA, with a designed restriction site to ensure simple and efficient mutant screening. The DNA sequence to be mutated was first translated into amino acid sequence and then the amino acid sequence was reversely translated into DNA sequence with degenerate codons, resulting in a large number of sequences with silent mutations, which contained various restriction endonuclease (RE) sites. Certain mutated sequence with an appropriate RE site was selected as the target DNA sequence for designing a pair of mutation primers to amplify the full-length plasmid via inverse PCR. The amplified product was 5'-phosphorylated, circularized, and transformed into an Escherichia coli host. The transformants were screened by digesting with the designed RE. This protocol uses only one pair of primers and only one PCR is conducted, without the need for hybridization with hazardous isotope for mutant screening or subcloning step.
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
authors.forename: Bao-zhong
authors.initials: BZ
authors.lastname: Zhang
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.forename: Xiao-ping
authors.initials: XP
authors.lastname: An
authors.forename: Duo-liang
authors.initials: DL
authors.lastname: Ran
authors.forename: Yu-sen
authors.initials: YS
authors.lastname: Zhou
authors.forename: Jun
authors.initials: J
authors.lastname: Lu
authors.forename: Yi-gang
authors.initials: YG
authors.lastname: Tong
mesh_terms: D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins / Q000235:genetics*; D005820:Genetic Testing / Q000379:methods*; D016297:Mutagenesis, Site-Directed / Q000379:methods*; D009154:Mutation / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods*
chemical_list: D029968:Escherichia coli Proteins