Building better polymerases: Engineering the replication of expanded genetic alphabets

Area of Science:

• Molecular Biology
• Biotechnology
• Synthetic Biology

Background:

• Natural DNA polymerases have limitations in replicating novel DNA structures.
• Synthetic biology requires DNA polymerases with enhanced capabilities for unnatural DNA.
• Rational engineering is crucial for developing specialized DNA polymerases.

Purpose of the Study:

• To review the properties of DNA polymerases and their engineered variants.
• To focus on the Klenow fragment of Taq DNA polymerase (Klentaq) and its evolution.
• To elucidate mechanisms for engineering DNA polymerases to replicate unnatural base pairs (UBPs).

Main Methods:

• Comparative structural, enzymatic, and molecular dynamics studies.
• Analysis of wild-type (WT) and Klentaq variants with natural and noncanonical substrates.
• Investigating amino acid substitutions in Klentaq variants, such as ZP Klentaq.

Main Results:

• Specific amino acid substitutions distant from the active site enhance UBP replication.
• ZP Klentaq demonstrates improved efficiency in replicating UBPs compared to Klentaq.
• Structural and dynamic studies provide mechanistic insights into enzyme performance.

Conclusions:

• Rational engineering can significantly improve DNA polymerase performance for unnatural DNA.
• Understanding structure-function relationships guides the development of novel DNA polymerases.
• This approach is applicable for future engineering of replicative DNA polymerases.