title: Optical characterization of glutamate dehydrogenase monolayers chemisorbed on SiO2.
abstract: This paper describes the formation of glutamate dehydrogenase monolayers on silicon dioxide, and their characterization by means of physical techniques, i.e., fluorescence spectroscopy and Fourier-transform infrared spectroscopy. Detailed investigations of the intrinsic stability of native proteins in solution were carried out to elucidate the occurrence of conformational changes induced by the immobilization procedure. The enzyme monolayers were deposited on SiO2 after preexposing silicon surfaces to 3-aminopropyltriethoxysilane and reacting the silylated surfaces with glutaric dialdehyde. The optical characterization demonstrates that the immobilization does not interfere with the fold pattern of the native enzyme. In addition, fluorescence spectroscopy, thermal denaturation, and quenching studies performed on the enzyme in solution well describe the folding and unfolding properties of glutamate dehydrogenase. The photophysical studies reported here are relevant for nanobioelectronics applications requiring protein immobilization on a chip.
authors.affiliation: National Nanotechnology Laboratories of INFM, Biomolecular Electronics Division, Department of Innovation Engineering, University of Lecce, Via per Arnesano, Italy.
authors.forename: P P
authors.initials: PP
authors.lastname: Pompa
authors.forename: L
authors.initials: L
authors.lastname: Blasi
authors.forename: L
authors.initials: L
authors.lastname: Longo
authors.forename: R
authors.initials: R
authors.lastname: Cingolani
authors.forename: G
authors.initials: G
authors.lastname: Ciccarella
authors.forename: G
authors.initials: G
authors.lastname: Vasapollo
authors.forename: R
authors.initials: R
authors.lastname: Rinaldi
authors.forename: A
authors.initials: A
authors.lastname: Rizzello
authors.forename: C
authors.initials: C
authors.lastname: Storelli
authors.forename: M
authors.initials: M
authors.lastname: Maffia
mesh_terms: D055592:Biophysical Phenomena; D001703:Biophysics; D005969:Glutamate Dehydrogenase / Q000737:chemistry*; D008027:Light; D011437:Propylamines; D011487:Protein Conformation; D012542:Scattering, Radiation; D012821:Silanes / Q000737:chemistry; D012825:Silicon / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013997:Time Factors; D014364:Tryptophan / Q000737:chemistry
chemical_list: D011437:Propylamines; D012821:Silanes; D012822:Silicon Dioxide; D014364:Tryptophan; D005969:Glutamate Dehydrogenase; C477625:amino-propyl-triethoxysilane; D012825:Silicon