title: Driving force behind adsorption-induced protein unfolding: a time-resolved X-ray reflectivity study on lysozyme adsorbed at an air/water interface.
abstract: Time-resolved X-ray reflectivity measurements for lysozyme (LSZ) adsorbed at an air/water interface were performed to study the mechanism of adsorption-induced protein unfolding. The time dependence of the density profile at the air/water interface revealed that the molecular conformation changed significantly during adsorption. Taking into account previous work using Fourier transform infrared (FTIR) spectroscopy, we propose that the LSZ molecules initially adsorbed on the air/water interface have a flat unfolded structure, forming antiparallel beta-sheets as a result of hydrophobic interactions with the gas phase. In contrast, as adsorption continues, a second layer forms in which the molecules have a very loose structure having random coils as a result of hydrophilic interactions with the hydrophilic groups that protrude from the first layer.
authors.affiliation: Synchrotron Light Life Science Center, Ritsumeikan University, 1-1-1 Noji-Higashi, Kusatsu-shi, Shiga 525-8577, Japan. y-yano@fc.ritsumei.ac.jp
authors.forename: Yohko F
authors.initials: YF
authors.lastname: Yano
authors.forename: Tomoya
authors.initials: T
authors.lastname: Uruga
authors.forename: Hajime
authors.initials: H
authors.lastname: Tanida
authors.forename: Hidenori
authors.initials: H
authors.lastname: Toyokawa
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Terada
authors.forename: Masafumi
authors.initials: M
authors.lastname: Takagaki
authors.forename: Hironari
authors.initials: H
authors.lastname: Yamada
mesh_terms: D000327:Adsorption; D000388:Air; D007700:Kinetics; D009113:Muramidase / Q000737:chemistry*; D011489:Protein Denaturation; D013499:Surface Properties; D014867:Water; D014965:X-Rays
chemical_list: D014867:Water; D009113:Muramidase