Mutant T4 DNA polymerase for easy cloning and mutagenesis

Area of Science:

• Molecular Biology
• Biochemistry

Background:

• High-fidelity DNA polymerases simplify plasmid cloning and mutagenesis.
• Commercially available kits often use proprietary components.

Purpose of the Study:

• To evaluate a mutant T4 DNA polymerase (Y320A) for generating single-stranded DNA overhangs.
• To improve yields in plasmid cloning and mutagenesis, particularly with low-competency E. coli.

Main Methods:

• Utilized a mutant T4 DNA polymerase (Y320A) with attenuated 3'-exonuclease activity.
• Applied the mutant enzyme in sequence and ligation independent cloning (SLIC) and modified QuikChange protocols.
• Assessed the enzyme's ability to generate uniform single-stranded DNA overhangs and suppress parental plasmid DNA.

Main Results:

• The mutant T4 DNA polymerase generated uniform single-stranded DNA overhangs controllably.
• Increased colony yields containing correctly modified plasmids in cloning and mutagenesis experiments.
• Enhanced yield of mutated plasmids and suppressed parental plasmid DNA in modified QuikChange method.

Conclusions:

• Mutant T4 DNA polymerase (Y320A) is effective for generating single-stranded DNA overhangs.
• The enzyme improves cloning and mutagenesis efficiency, especially for low-competency E. coli.
• Facilitates plasmid circularization, annealing, and ligation in E. coli.