title: FTIR and XPS studies of protein adsorption onto functionalized bioactive glass.
abstract: Adsorption and structural changes that occur upon interaction between methemoglobin (MetHb) and 5-methyl-aminomethyl-uridine forming enzyme (MnmE) with the surface of a bioactive glass (BG) were investigated by Fourier Transform Infrared (FTIR) spectroscopy and X-ray Photoelectron Spectroscopy (XPS). The effect of glutaraldehyde (GA) as a coupling agent for protein adsorption on BG was also investigated. The comparative analysis of FTIR spectra recorded from lyophilized proteins and from bioactive glass surface after protein adsorption was considered in order to obtain information about the changes in the secondary structure of the proteins. XPS data were used to determine the surface coverage. The unfolding of adsorbed proteins due to interactions between the internal hydrophobic protein domains and the hydrophobic BG surface was evidenced. After adsorption, the amount of α-helix decreases and less ordered structures (turns, random coils and aggregates) are preponderant. These changes are less pronounced on the BG functionalized with GA, suggesting that the treatment with GA preserves significantly larger amounts of α-helices in the structure of both proteins after adsorption.
authors.affiliation: Babes-Bolyai University, Cluj-Napoca, Romania.
authors.forename: C
authors.initials: C
authors.lastname: Gruian
authors.forename: E
authors.initials: E
authors.lastname: Vanea
authors.forename: S
authors.initials: S
authors.lastname: Simon
authors.forename: V
authors.initials: V
authors.lastname: Simon
mesh_terms: D000327:Adsorption; D000818:Animals; D030562:Databases, Protein; D004926:Escherichia coli / Q000737:chemistry; D029968:Escherichia coli Proteins / Q000737:chemistry*; D020558:GTP Phosphohydrolases / Q000737:chemistry*; D005898:Glass / Q000737:chemistry*; D005976:Glutaral / Q000737:chemistry; D006736:Horses / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D008706:Methemoglobin / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties
chemical_list: D029968:Escherichia coli Proteins; D008706:Methemoglobin; D020558:GTP Phosphohydrolases; C492932:MnmE protein, E coli; D005976:Glutaral