Parallel tempering Monte Carlo simulations of lysozyme orientation on charged surfaces.
In this work, the parallel tempering Monte Carlo (PTMC) algorithm is applied to accurately and efficiently identify the global-minimum-energy orientation of a protein adsorbed on a surface in a single simulation. When applying the PTMC method to simulate lysozyme orientation on charged surfaces, it is found that lysozyme could easily be adsorbed on negatively charged surfaces with "side-on" and "back-on" orientations. When driven by dominant electrostatic interactions, lysozyme tends to be adsorbed on negatively charged surfaces with the side-on orientation for which the active site of lysozyme faces sideways. The side-on orientation agrees well with the experimental results where the adsorbed orientation of lysozyme is determined by electrostatic interactions. As the contribution from van der Waals interactions gradually dominates, the back-on orientation becomes the preferred one. For this orientation, the active site of lysozyme faces outward, which conforms to the experimental results where the orientation of adsorbed lysozyme is co-determined by electrostatic interactions and van der Waals interactions. It is also found that despite of its net positive charge, lysozyme could be adsorbed on positively charged surfaces with both "end-on" and back-on orientations owing to the nonuniform charge distribution over lysozyme surface and the screening effect from ions in solution. The PTMC simulation method provides a way to determine the preferred orientation of proteins on surfaces for biosensor and biomaterial applications.
Guangdong Provincial Key Lab for Green Chemical Product Technology, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, Guangdong 510640, People's Republic of China.
Yun
Y
Xie
Jian
J
Zhou
Shaoyi
S
Jiang
D000327:Adsorption; D000465:Algorithms; D000818:Animals; D002645:Chickens; D008956:Models, Chemical; D008958:Models, Molecular; D009010:Monte Carlo Method; D009113:Muramidase / Q000737:chemistry*; D011487:Protein Conformation; D055672:Static Electricity; D013499:Surface Properties
D009113:Muramidase