Application of a Rational Crystal Contact Engineering Strategy on a Poly(ethylene terephthalate)-Degrading Cutinase

Area of Science:

• Biotechnology
• Protein Crystallography
• Enzymatic Recycling

Background:

• Industrial biotechnology utilizes enzymes for PET recycling under mild conditions.
• Leaf branch compost cutinase (LCC) quadruple mutant ICCG is a key biocatalyst.
• Efficient downstream processing of ICCG is crucial for its application.

Purpose of the Study:

• To improve the crystallizability of ICCG using crystal contact engineering.
• To explore the extension of electrostatic interactions for enhanced protein crystallization.
• To demonstrate the rational design of protein mutants for improved crystallization.

Main Methods:

• Engineering ICCG by introducing specific amino acid substitutions (L50Y, T110E) to create electrostatic interactions at crystal contacts.
• Utilizing Arg-Glu interactions to enhance crystallizability.
• Introducing control mutations at non-contact sites to validate the engineering strategy.

Main Results:

• ICCG mutant L50Y (ICCGY) and ICCGY T110E showed improved crystallizability.
• The Arg-Glu interaction strategy proved effective in enhancing crystallization.
• Control mutants did not show superior crystallization compared to wild-type ICCG.

Conclusions:

• Crystal contact engineering is a promising strategy for rationally enhancing protein crystallization.
• This approach can significantly streamline downstream processing in biotechnology.
• The findings offer a more efficient pathway for industrial enzyme applications and PET recycling.