Modeling Temperature-Dependent Protein Structural Transitions by Combined Near-IR and Mid-IR Spectroscopies and Multivariate Curve Resolution

Abstract

The combination of near- and midinfrared spectroscopies (NIR and MIR) is proposed to monitor temperature-dependent transitions of proteins. These techniques offer a high discriminating power to distinguish among protein structural conformations but, in temperature-dependent processes, present the drawback associated with the intense and evolving absorption of the deuterium oxide, used as a solvent in the protein solutions. Multivariate curve resolution-alternating least squares (MCR-ALS) is chosen as the data analysis technique able to unravel the contributions of the pure protein and deuterium oxide species from the mixed raw experimental measurements. To do so, MCR-ALS works by analyzing simultaneously experiments from MIR and NIR on pure deuterium oxide solutions and protein solutions in D2O. This strategy has proven to be effective for modeling the protein process in the presence of D2O and, therefore, for avoiding the inclusion of artifacts in the data stemming from inadequate baseline corrections. The use of MIR and NIR and MCR-ALS has been tested in the study of the temperature-dependent evolution of beta-lactoglobulin. Only the combined use of these two infrared techniques has allowed for the distinction of the three pure conformations involved in the process in the working thermal range: native, R-type state, and molten globule.

Comparison of two methods for extraction of dill essential oil by gas chromatography-mass spectrometry coupled with chemometric resolution techniques

“…The multivariate curve resolution (MCR) has been shown to be a powerful tool for the investigation of complex chemical systems, particularly for the investigation of chemical systems about which there was little or no previous knowledge. [33,34] The MCR methods perform the decomposition of an experimental data matrix in the production of two simpler matrices, one related to the rows of the original data matrix (usually related to the changes in chemical composition) and another related to the columns of the original matrix (usually related to the measured instrumental or spectroscopic changes). The MCR methods can be divided into iterative and noniterative types.…”

Spectroscopic Characterization of Thiazole Orange-3 DNA Interaction

“…The first one is determination of the number of components, i.e., the number of complexes. A first estimation of the number of complexes is obtained from singular value decomposition (SVD) [55], although this number must be considered as an approximation and the definitive number of process contributions will be defined by the resolution results. The second step is construction of an initial estimate of either the C or the S T matrix derived from chemometric methods, such as evolving factor analysis (EFA) [56,57] or methods based on the selection of the purest variables [58,59], or from the selection of representative spectra.…”

Near infrared spectroscopy and multivariate curve resolution‐alternating least squares incorporating 13C‐NMR information for monitoring epoxy resins reactions

“…Near infrared spectroscopy (NIR) in combination with multivariate curve resolution methods has demonstrated to be a useful technique in many analytical applications due to the combination of an instrumental technique that incorporates an easy-to-obtain analytical signal with a powerful chemometric technique that can achieve the necessary spectral resolution [1][2][3][4]. Soft-modeling methods, in particular the multivariate curve resolution-alternating least squares method (MCR-ALS), have great potential when applied to spectroscopic data obtained from monitoring a chemical reaction, so the concentration profiles of each species involved in the reaction and the corresponding pure spectra can be estimated [5][6][7].…”

“…Multivariate curve resolution has been used to combine such spectroscopic techniques as fluorescence and circular dichroism [13], near infrared and mid infrared [4] and mass spectrometry and circular dichroism [14]. It also makes it possible to combine UV-Vis and near infrared with calorimetric techniques [15,16].…”