title: Effect of the protonation degree of a self-assembled monolayer on the immobilization dynamics of a [NiFe] hydrogenase.
abstract: Understanding the interaction and immobilization of [NiFe] hydrogenases on functionalized surfaces is important in the field of biotechnology and, in particular, for the development of biofuel cells. In this study, we investigated the adsorption behavior of the standard [NiFe] hydrogenase of  Desulfovibrio gigas  on amino-terminated alkanethiol self-assembled monolayers (SAMs) with different levels of protonation. Classical all-atom molecular dynamics (MD) simulations revealed a strong correlation between the adsorption behavior and the level of ionization of the chemically modified electrode surface. While the hydrogenase undergoes a weak but stable initial adsorption process on SAMs with a low degree of protonation, a stronger immobilization is observable on highly ionized SAMs, affecting protein reorientation and conformation. These results were validated by complementary surface-enhanced infrared absorption (SEIRA) measurements on the comparable [NiFe] standard hydrogenases from  Desulfovibrio vulgaris  Miyazaki F and allowed in this way for a detailed insight into the adsorption mechanism at the atomic level.
authors.affiliation: Institut für Chemie, Technische Universität Berlin, Berlin, Germany.
authors.forename: Tillmann
authors.initials: T
authors.lastname: Utesch
authors.forename: Diego
authors.initials: D
authors.lastname: Millo
authors.forename: Maria Ana
authors.initials: MA
authors.lastname: Castro
authors.forename: Peter
authors.initials: P
authors.lastname: Hildebrandt
authors.forename: Ingo
authors.initials: I
authors.lastname: Zebger
authors.forename: Maria Andrea
authors.initials: MA
authors.lastname: Mroginski
mesh_terms: D000327:Adsorption; D000473:Alkanes / Q000737:chemistry; D001426:Bacterial Proteins / Q000737:chemistry*; D045286:Desulfovibrio gigas / Q000737:chemistry* / Q000201:enzymology; D016969:Desulfovibrio vulgaris / Q000737:chemistry* / Q000201:enzymology; D004566:Electrodes; D006046:Gold / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D006864:Hydrogenase / Q000737:chemistry*; D055767:Immobilized Proteins / Q000737:chemistry*; D007700:Kinetics; D056004:Molecular Dynamics Simulation; D011522:Protons; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013816:Thermodynamics
chemical_list: D000473:Alkanes; D001426:Bacterial Proteins; D055767:Immobilized Proteins; D011522:Protons; D013438:Sulfhydryl Compounds; D006046:Gold; C043296:nickel-iron hydrogenase; D006864:Hydrogenase