Principal component analysis of the pH-dependent conformational transitions of bovine beta-lactoglobulin monitored by heteronuclear NMR.

ABSTRACT: To clarify the pH-dependent conformational transitions of proteins, we propose an approach in which structural changes monitored by heteronuclear sequential quantum correlation (HSQC) spectroscopy were analyzed by using a principal component analysis (PCA). We use bovine beta-lactoglobulin, a protein widely used in protein folding studies, as a target. First, we measured HSQC spectra at various pH values and subjected them to a PCA. The analysis revealed three apparent transitions with pK(a) values of 2.9, 4.9, and 6.8, consistent with previous reports using different methods. Next, Gdn-HCl-induced unfolding was examined by measuring tryptophan fluorescence at various pH values. Between pH 2 and 8, beta-lactoglobulin exhibited a number of structural transitions as well as changes in stabil

SUBMITTER: Sakurai K 

PROVIDER: S-EPMC2000507 | biostudies-literature | 2007 Sep

REPOSITORIES: biostudies-literature