title: An investigation of the effects of self-assembled monolayers on protein crystallisation.
abstract: Most protein crystallisation begins from heterogeneous nucleation; in practice, crystallisation typically occurs in the presence of a solid surface in the solution. The solid surface provides a nucleation site such that the energy barrier for nucleation is lower on the surface than in the bulk solution. Different types of solid surfaces exhibit different surface energies, and the nucleation barriers depend on the characteristics of the solid surfaces. Therefore, treatment of the solid surface may alter the surface properties to increase the chance to obtain protein crystals. In this paper, we propose a method to modify the glass cover slip using a self-assembled monolayer (SAM) of functional groups (methyl, sulfydryl and amino), and we investigated the effect of each SAM on protein crystallisation. The results indicated that both crystallisation success rate in a reproducibility study, and crystallisation hits in a crystallisation screening study, were increased using the SAMs, among which, the methyl-modified SAM demonstrated the most significant improvement. These results illustrated that directly modifying the crystallisation plates or glass cover slips to create surfaces that favour heterogeneous nucleation can be potentially useful in practical protein crystallisation, and the utilisation of a SAM containing a functional group can be considered a promising technique for the treatment of the surfaces that will directly contact the crystallisation solution.
authors.affiliation: Institute for Special Environmental Biophysics, Key Laboratory for Space Bioscience and Biotechnology, School of Life Sciences, Northwestern Polytechnical University, Xi'an 710072, Shaanxi, China. yindc@nwpu.edu.cn.
authors.forename: Chen-Yan
authors.initials: CY
authors.lastname: Zhang
authors.forename: He-Fang
authors.initials: HF
authors.lastname: Shen
authors.forename: Qian-Jin
authors.initials: QJ
authors.lastname: Wang
authors.forename: Yun-Zhu
authors.initials: YZ
authors.lastname: Guo
authors.forename: Jin
authors.initials: J
authors.lastname: He
authors.forename: Hui-Ling
authors.initials: HL
authors.lastname: Cao
authors.forename: Yong-Ming
authors.initials: YM
authors.lastname: Liu
authors.forename: Peng
authors.initials: P
authors.lastname: Shang
authors.forename: Da-Chuan
authors.initials: DC
authors.lastname: Yin
mesh_terms: D000327:Adsorption; D011232:Chemical Precipitation; D003460:Crystallization; D018625:Microscopy, Atomic Force; D008958:Models, Molecular; D056951:Photoelectron Spectroscopy; D011506:Proteins / Q000737:chemistry*; D015203:Reproducibility of Results; D012821:Silanes / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D011506:Proteins; D012821:Silanes