Simultaneous Fitting of Absorption Spectra and Their Second Derivatives for an Improved Analysis of Protein Infrared Spectra

Molecules

Maurizio Baldassarre¹  Chenge Li¹  Nadejda Eremina¹  Erik Goormaghtigh²  Andreas Barth¹ 

[1]Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden

[2] E-Mails:

[3]Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles, 1050 Brussels, Belgium

[4] E-Mail:

关键词: Fourier-transform infrared spectroscopy;    FT-IR;    curve fitting;    amide I;    secondary structure;    second derivative;   

DOI  :  10.3390/molecules200712599

来源: mdpi

【 摘 要 】

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.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.