Automating gene library synthesis by structure-based combinatorial protein engineering: examples from plant...

Area of Science:

• Protein Engineering
• Molecular Biology
• Biotechnology

Background:

• DNA shuffling mimics meiotic recombination for gene diversification but requires sequence identity.
• Protein structure conservation and sequence degeneracy necessitate alternative recombination methods for distantly related genes.

Purpose of the Study:

• To present a simplified protocol for Structure-based combinatorial protein engineering (SCOPE), a homology-independent gene recombination technique.
• To demonstrate SCOPE's application in creating diverse gene libraries for exploring protein functional divergence, using plant sesquiterpene synthases as a model system.

Main Methods:

• SCOPE utilizes oligonucleotides to encode crossover regions, directing template-switching events during PCR assembly of gene fragments.
• The method enables the creation of chimeric genes from distantly related parents, independent of sequence homology.
• A simplified SCOPE protocol is presented, suitable for integration with mutagenesis techniques and automation.

Main Results:

• SCOPE successfully generated combinatorial mutant libraries of plant sesquiterpene synthases.
• Two examples illustrate the creation of an active-site library (complex mixtures) and a focused library (individual clones).
• The study highlights the technique's versatility in exploring catalytic landscapes and functional divergence.

Conclusions:

• SCOPE provides a powerful, homology-independent approach for protein engineering and generating diverse gene libraries.
• The method is adaptable for creating both complex and focused mutant libraries, facilitating the study of enzyme function.
• Automation potential of SCOPE is discussed for various applications in protein research.