Cofactor specificity switch in Shikimate dehydrogenase by rational design and consensus engineering.

Area of Science:

• Protein Engineering
• Enzyme Design
• Biochemistry

Background:

• Consensus engineering typically enhances protein stability by selecting frequent amino acids from alignments.
• Previous efforts focused on stability, with functional modifications being secondary.
• Shikimate dehydrogenase enzymes are crucial in metabolic pathways.

Purpose of the Study:

• To construct a consensus Rossmann domain for Shikimate dehydrogenase.
• To switch cofactor specificity of E. coli Shikimate dehydrogenase via rational design.
• To investigate the impact of consensus mutations on the engineered enzyme's activity and stability.

Main Methods:

• Multiple sequence alignment and consensus sequence generation.
• Rational design for cofactor specificity switching.
• Site-directed mutagenesis to introduce consensus mutations.
• Enzyme activity assays to quantify functional changes.

Main Results:

• A consensus Rossmann domain was successfully constructed.
• Cofactor specificity was altered through rational design.
• Consensus mutations near the 2' adenine moiety significantly increased enzyme activity in the designed variant.
• The study confirmed consensus engineering's role in protein stabilization.

Conclusions:

• Consensus engineering can be a valuable tool for enhancing enzyme activity, not just stability.
• Strategic placement of consensus mutations can modulate enzyme function.
• This approach offers a complementary strategy for protein design and optimization.