title: Morphology of dry solid-supported protein monolayers dependent on the substrate and protein surface properties.
abstract: The morphologies of dry MrgA protein monolayers on different solid substrates prepared by a three-step procedure (adsorption from an incubation solution, rinsing to remove excess salt and protein, and drying) were investigated using atomic force microscopy. MrgA is a dodecameric iron-storage protein which can form hexagonal, two-dimensional (2D) crystalline monolayers on hydrophilic surfaces at low supersaturation. The formation of such two-dimensional crystals is heavily dependent on the pH and the salinity of the incubation solution as well as on the surface properties. Correlation of surface coverage with substrate charge, ionic strength, and pH indicates the dominance of electrostatic effects in adsorption, with the balance shifting between intermolecular repulsion and protein-substrate attraction. Close to the isoelectric point (pI) of MrgA, adsorption to the surface and the formation of 2D crystals are favored. By preparation of self-assembled monolayers of thiols with different end groups on template-stripped gold, the surface properties can be varied easily from high to very low protein affinity. The resulting patterns of the crystalline protein structures are novel and could be a starting point for further scientific study, e.g., solid-supported cocrystallization with DNA, and indeed developments with technological applications, such as mesostructured deposition of MrgA-caged nanoparticles.
authors.affiliation: Faculty of Chemistry and Materials Sciences Center, University of Marburg, Hans-Meerwein-Strasse, D-35032 Marburg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Schönafinger
authors.forename: Anke
authors.initials: A
authors.lastname: Morbitzer
authors.forename: Daniel
authors.initials: D
authors.lastname: Kress
authors.forename: Lars-Oliver
authors.initials: LO
authors.lastname: Essen
authors.forename: Frank
authors.initials: F
authors.lastname: Noll
authors.forename: Norbert
authors.initials: N
authors.lastname: Hampp
mesh_terms: D000327:Adsorption; D000538:Aluminum Silicates / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry*; D003460:Crystallization; D004268:DNA-Binding Proteins / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007477:Ions; D018625:Microscopy, Atomic Force; D008958:Models, Molecular; D008962:Models, Theoretical; D012825:Silicon / Q000737:chemistry*; D013379:Substrate Specificity; D013499:Surface Properties
chemical_list: D000538:Aluminum Silicates; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D007477:Ions; C095506:MrgA protein, Bacillus subtilis; D006046:Gold; C011934:mica; D012825:Silicon