Orthogonal combinatorial mutagenesis: a codon-level combinatorial mutagenesis method useful for low multiplicity and...

Area of Science:

• Molecular Biology
• Synthetic Biology
• Biotechnology

Background:

• Generating diverse mutant libraries is crucial for protein engineering and functional genomics.
• Existing methods may lack precise control over mutagenesis rates and mutant distribution.
• Need for efficient, automated techniques for creating codon-level mutations.

Purpose of the Study:

• To develop and validate a method for generating codon-level mutated oligonucleotide libraries.
• To achieve controlled mutagenesis rates and predictable binomial distributions of mutants.
• To facilitate applications such as directed evolution and alanine scanning.

Main Methods:

• Utilized two sets of deoxynucleoside-phosphoramidites with orthogonal protecting groups (DMT and Fmoc).
• Employed divergent synthesis in a single column, combining wild-type (DMT) and mutant (Fmoc) codons.
• Automated synthesis in an NNG/C fashion to control mutagenesis rate and precursor concentration.

Main Results:

• Successfully generated oligonucleotide libraries with controlled codon-level mutations.
• Demonstrated predictable binomial distributions of mutants based on chosen mutagenesis rates.
• Validated the method's performance through cloning and sequencing of 129 clones.

Conclusions:

• The described method provides precise control over mutagenesis rates for oligonucleotide library generation.
• This technique is automated, efficient, and suitable for low mutagenesis rates and large-scale applications.
• The method is effective for generating libraries for directed evolution and alanine scanning studies.