Abstract
Bovine milk beta-lactoglobulin (BLG) is a small whey protein that is a common ingredient in many foods. Many of the properties of BLG relevant to the food industry are related to its unfolding processes induced by physical or chemical treatments. Unfolding occurs through a number of individual steps, generating transient intermediates through reversible and irreversible modifications. The rate of formation of these intermediates and of their further evolution into different structures often dictates the outcome of a given process. This report addresses the main structural features of the BLG unfolding intermediates under conditions that may facilitate or impair their formation in response to chemical or physical denaturing agents. In consideration of the short lifespan of the transient species generated upon unfolding, this review also discusses how various methodological approaches may be adapted in exploring the process-dependent structural modifications of BLG from a kinetic and/or a thermodynamic standpoint. Some of the conceptual and methodological approaches presented and discussed in this review can provide hints for improving the understanding of transient conformers formation by proteins present in other food systems, as well as when other physical or chemical denaturing agents are acting on proteins much different from BLG in complex food systems.
Highlights
Beta-lactoglobulin from bovine milk is a small protein of 162 residues with a molecular mass of 18,281 Da (UniProtKB P02754) [1], and is present as a noncovalent homodimer in cow milk, a difference from the protein in milk from other species, such as mare or donkey
This review focuses on the concept that controlled unfolding of proteins is central to any process that implies the conversion of raw materials into foods suitable for human use from a number of standpoints: from accessibility of nutrients to removal of antinutritional factors, from inactivation of spoiling enzymes to microbiological safety, and including imparting desirable sensory traits to the processed food [2]
BLG has a number of molecular traits that make it well suited for addressing the nature, the rate of formation/decay, and the eventual fate of unfolding intermediates generated by processes of relevance to the food industry
Summary
Beta-lactoglobulin from bovine milk is a small protein of 162 residues with a molecular mass of 18,281 Da (UniProtKB P02754) [1], and is present as a noncovalent homodimer in cow milk, a difference from the protein in milk from other species, such as mare or donkey. BLG is an excellent model for studies on individual determinants of process-induced conformational changes, as this protein offers the possibility of monitoring modifications in specific regions of the protein by exploiting different instrumental signals or by using a variety of methodological approaches. In addition to spectroscopy, calorimetry, and other biophysical approaches, several studies based on bioinformatics modeling tools have appeared All these studies addressed only very sporadically—if at all—the issues dealt with in the current review and concerning the impact of noncovalently bound ligands on the stability of the structure of BLG toward chemical and physical denaturation, as well as the rate of formation, the reactivity, and the lifespan of transiently/partially unfolded BLG molecules that may be formed in the process. The properties of the “active monomer” generated by either chaotrope at subdenaturing concentrations and the mechanism leading to the formation of ordered polymers have been analyzed elsewhere [24], but it seems appropriate to underscore once again that the structural features of the “transient conformer” generated in the earliest steps of exposure to chemical denaturants dictate the rate and the fate of the subsequent (and much slower) formation of polymers of regular geometry
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
