title: Simultaneous Fitting of Absorption Spectra and Their Second Derivatives for an Improved Analysis of Protein Infrared Spectra.
abstract: Infrared spectroscopy is a powerful tool in protein science due to its sensitivity to changes in secondary structure or conformation. In order to take advantage of the full power of infrared spectroscopy in structural studies of proteins, complex band contours, such as the amide I band, have to be decomposed into their main component bands, a process referred to as curve fitting. In this paper, we report on an improved curve fitting approach in which absorption spectra and second derivative spectra are fitted simultaneously. Our approach, which we name co-fitting, leads to a more reliable modelling of the experimental data because it uses more spectral information than the standard approach of fitting only the absorption spectrum. It also avoids that the fitting routine becomes trapped in local minima. We have tested the proposed approach using infrared absorption spectra of three mixed α/β proteins with different degrees of spectral overlap in the amide I region: ribonuclease A, pyruvate kinase, and aconitase.
authors.affiliation: Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden. maurizio.baldassarre@dbb.su.se.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Baldassarre
authors.affiliation: Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden. chenge.li@dbb.su.se.
authors.forename: Chenge
authors.initials: C
authors.lastname: Li
authors.affiliation: Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden. naer2045@dbb.su.se.
authors.forename: Nadejda
authors.initials: N
authors.lastname: Eremina
authors.affiliation: Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles, 1050 Brussels, Belgium. egoor@ulb.ac.be.
authors.forename: Erik
authors.initials: E
authors.lastname: Goormaghtigh
authors.affiliation: Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden. andreas.barth@dbb.su.se.
authors.forename: Andreas
authors.initials: A
authors.lastname: Barth
mesh_terms: D000154:Aconitate Hydratase / Q000737:chemistry* / Q000302:isolation & purification; D000818:Animals; D002021:Buffers; D002417:Cattle; D018482:Muscle, Skeletal / Q000737:chemistry / Q000201:enzymology; D009206:Myocardium / Q000737:chemistry / Q000201:enzymology; D010179:Pancreas / Q000737:chemistry / Q000201:enzymology; D017433:Protein Structure, Secondary; D011770:Pyruvate Kinase / Q000737:chemistry* / Q000302:isolation & purification; D011817:Rabbits; D012259:Ribonuclease, Pancreatic / Q000737:chemistry* / Q000302:isolation & purification; D012996:Solutions; D017550:Spectroscopy, Fourier Transform Infrared / Q000706:statistics & numerical data*; D013552:Swine
chemical_list: D002021:Buffers; D012996:Solutions; D011770:Pyruvate Kinase; D012259:Ribonuclease, Pancreatic; D000154:Aconitate Hydratase
keywords: FT-IR; Fourier-transform infrared spectroscopy; amide I; curve fitting; second derivative; secondary structure