Modelling of microbial polyhydroxyalkanoate surface binding protein PhaP for rational mutagenesis

Abstract

Summary Phasins are unusual amphiphilic proteins that bind to microbial polyhydroxyalkanoate ( PHA ) granules in nature and show great potential for various applications in biotechnology and medicine. Despite their remarkable diversity, only the crystal structure of Pha P A h from Aeromonas hydrophila has been solved to date. Based on the structure of Pha P A h , homology models of Pha P A z from Azotobacter sp . FA ‐8 and Pha P TD from Halomonas bluephagenesis TD were successfully established, allowing rational mutagenesis to be conducted to enhance the stability and surfactant properties of these proteins. Pha P A z mutants, including Pha P A z Q38L and Pha P A z Q78L, as well as Pha P TD mutants, including Pha P TD Q 38M and Pha P TD Q 72M, showed better emulsification properties and improved thermostability (6‐10°C higher melting temperatures) compared with their wild‐type homologues under the same conditions. Importantly, the established PhaP homology‐modelling approach, based on the high‐resolution structure of Pha P A h , can be generalized to facilitate the study of other PhaP members.

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Identifiers

DOI

10.1111/1751-7915.12820

Journal

Microbial Biotechnology

Year

2017