A Computational Approach to Modeling a Thermophilic Psychrophilic Protease Fusion Protein for Laundry Detergent

Protease is one of the main enzyme which is used in laundry industry. As the thermal condition in lanundryindustry is varied from high to low temperature, having protease enzyme which could activate in broadthermal range has great potential. One of the approach in this field is fusion two proteins with differentthermal activity. For doing this in current work by computational method, Thermolysin protease anextracellular metalloendopeptidase from a gram-positive thermophilic bacterium Bacillusthermoproteolyticus which activate in thermal range from ۲۵ to ۸۸°C, was joined by a four repeat of G۴S asa flexible linker with a psychrophilic protease from a marine bacterium Flavobacterium YS-۸۰ with thermalrange from ۰°C to ۳۰°C, to produce protease enzyme which activate in broad thermal range from ۰ to ۸۸° C.Material and methods:As the whole structure of thermolysin did not exist in PDB bank, homology modeling by Lomet webserverwas performed and Modeller package was applied to construct whole protein fusion structure. The quality ofmodel structure was verified by Procheck, Verify۳D, ERRAT, ProSA webserver. The secondary structureanalysis was done by PSIPRED. The solubility and physiochemical properties of fusion protein wasdetermined by Protein-sol and Protparam webserver. Molecular Dynamics simulation was perfomed byGromacs package to assess stability of fusion protein structure in simulated condition.Result and Discussion:The quality structure assessment of fusion protein showed that this protein modelled with high qualitycompared to non-fusion form. Also, secondary structure analysis revealed that no secondary structurechanges was observed in fusion form compared to non-fusion form. The physicochemical properties of fusionprotein figured out this structure had stable structure and good solubility in water. the Molecular dynamicsimulation result discovered that no drastic structure changes was happened during simulation time.

Keywords:

protease , protein engineering , homology modeling , molecular dynamics simulation