title: Conformational change of bovine serum albumin molecules at neutral pH in ultra-diluted aqueous solutions.
abstract: Surface chemical and electrochemical techniques were applied to reveal the unfolding of bovine serum albumin (BSA) molecules induced by concentrations in aqueous solution. Real-time surface pressures vs time (π-t) kinetic curves were recorded over an aqueous subphase (190 mL) by spreading BSA solutions of different concentrations but of the same amount (8.0 × 10(-4) mg) at the air/water (A/W) interface. A critical concentration (∼1.0 ppm) was discovered below which the surface pressure declines with time and the BSA is totally solubilized in the water subphase. Above this critical concentration (e.g., 8.0 ppm), the surface pressure goes up and the protein molecules assemble into a Langmuir monolayer at the A/W interface. These findings demonstrate that the BSA molecules have different conformations in the spreading protein solutions. The conformational transition in BSA molecules induced by concentrations was also confirmed by spectroscopy means and the catalytic hydrogen evolution reaction on a silver amalgam electrode by using constant current chronopotentiometric stripping. This discovery fills in gaps of Foster's N (normal) → F (fast) model, in which the unfolding of BSA molecules occurs at neutral pH values (8.0-4.3).
authors.affiliation: Anhui Key Lab of Controllable Chemical Reaction & Material Chemical Engineering, School of Chemical Engineering, Hefei University of Technology , Tunxi Road 193, 230009, Hefei, Anhui, China.
authors.forename: Shulian
authors.initials: S
authors.lastname: He
authors.forename: Mei
authors.initials: M
authors.lastname: Huang
authors.forename: Wei
authors.initials: W
authors.lastname: Ye
authors.forename: Dechao
authors.initials: D
authors.lastname: Chen
authors.forename: Shuai
authors.initials: S
authors.lastname: He
authors.forename: Liping
authors.initials: L
authors.lastname: Ding
authors.forename: Yunjin
authors.initials: Y
authors.lastname: Yao
authors.forename: Lei
authors.initials: L
authors.lastname: Wan
authors.forename: Jinzhang
authors.initials: J
authors.lastname: Xu
authors.forename: Shiding
authors.initials: S
authors.lastname: Miao
mesh_terms: D000818:Animals; D002417:Cattle; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D011487:Protein Conformation; D058767:Protein Unfolding; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D012996:Solutions; D014867:Water / Q000737:chemistry*
chemical_list: D012996:Solutions; D014867:Water; D012710:Serum Albumin, Bovine