Characterization of covalently bonded proteins on poly(methyl methacrylate) by X-ray photoelectron spectroscopy.
X-ray photoelectron spectroscopy (XPS) has been used to characterize a poly(methyl methacrylate) (PMMA) surface with covalently attached proteins. The PMMA surfaces were first aminated using hexamethyldiamine; the resulting -NH(2) sites were reacted with the hetero-bifunctional cross-linker Sulfo-EMCS to form a maleimide-terminated surface. The N-hydroxysuccinimide ester terminal and maleimide terminal groups of Sulfo-EMCS reacts with amine and sulfhydryl groups, respectively, exposed on the surface of the proteins. This study characterizes Thermotoga maritima beta-glucosidase 1 (TmGH1), which belongs to a family of proteins that facilitate hydrolysis of glucose-related monomers with retention of conformation. The surfaces were characterized by XPS to monitor surface composition, and to elucidate protein orientation on the surface. Results suggest that a covalently bonded surface of TmGH1 on PMMA has been obtained. These results demonstrate the feasibility of using XPS to study protein surface chemistry and demonstrate a useful method to anchor cysteine-terminated proteins for the purposes of creating biosensors or platforms for mechanical force experiments to investigate protein structure.
Nelson
Geoffrey W
GW
Department of Chemistry, Queen's University, Kingston, Ontario, Canada.
Perry
Megan
M
He
Shu-Mei
SM
Zechel
David L
DL
Horton
J Hugh
JH
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D018360:Crystallography, X-Ray; D004602:Elements; D008969:Molecular Sequence Data; D056951:Photoelectron Spectroscopy; D019904:Polymethyl Methacrylate / Q000737:chemistry / Q000378:metabolism*; D013499:Surface Properties; D020124:Thermotoga maritima / Q000201:enzymology*; D001617:beta-Glucosidase / Q000737:chemistry / Q000378:metabolism*
D001426:Bacterial Proteins; D004602:Elements; D019904:Polymethyl Methacrylate; D001617:beta-Glucosidase