Modelling of microbial polyhydroxyalkanoate surface binding protein PhaP for rational mutagenesis.

ABSTRACT: 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 PhaP_Ah from Aeromonas hydrophila has been solved to date. Based on the structure of PhaP_Ah , homology models of PhaP_Az from Azotobacter sp. FA-8 and PhaP_TD from Halomonas bluephagenesis TD were successfully established, allowing rational mutagenesis to be conducted to enhance the stability and surfactant properties of these proteins. PhaP_Az mutants, including PhaP_Az Q38L and PhaP_Az Q78L, as well as PhaP_TD mutants, including PhaP_TD Q38M and PhaP_TD Q72M, 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 PhaP_Ah , can be generalized to facilitate the study of other PhaP members.

SUBMITTER: Zhao H 

PROVIDER: S-EPMC5658623 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature