The denatured states of proteins have always attracted our attention due to the fact that the denatured state is the only experimentally achievable state of a protein, which can be taken as initial reference state for considering the in vitro folding and defining the native protein stability. It is known that heat and guanidinium chloride (GdmCl) give structurally different states of RNase-A, l...

Liu et al. (1) alleged that they could not repeat our work on the protein BBL (Protein Data Bank ID code 1W4H) at the most basic level. Campos and Muñoz now admit (2), as we explained (3), that they used a phosphate buffer that greatly changed pH during the guanidinium chloride (GdmCl) titration relative to our Mops buffer. They can now repeat our work. However, the authors now claim (2), misle...

The Bacillus licheniformis 749/I BlaI repressor is a prokaryotic regulator that, in the absence of a beta-lactam antibiotic, prevents the transcription of the blaP gene, which encodes the BlaP beta-lactamase. The BlaI repressor is composed of two structural domains. The 82-residue NTD (N-terminal domain) is a DNA-binding domain, and the CTD (C-terminal domain) containing the next 46 residues is...

The mechanism by which urea and guanidinium destabilize protein structure is controversial. We tested the possibility that these denaturants form hydrogen bonds with peptide groups by measuring their ability to block acid- and base-catalyzed peptide hydrogen exchange. The peptide hydrogen bonding found appears sufficient to explain the thermodynamic denaturing effect of urea. Results for guanid...

Dry molten globular (DMG) intermediates, an expanded form of the native protein with a dry core, have been observed during denaturant-induced unfolding of many proteins. These observations are counterintuitive because traditional models of chemical denaturation rely on changes in solvent-accessible surface area, and there is no notable change in solvent-accessible surface area during the format...

Lipoate acetyltransferase (E2) forms the core of the pyruvate dehydrogenase multienzyme complex (reviewed [ 1,2]). The subunit Mr of mammalian E2 has been a matter of controversy. Using SDS-polyacrylamide gel electrophoresis Mr 74 000-76 000 has been found for the bovine as well as porcine kidney and heart enzyme [3-61. The same value was reported for pig heart E2 in a study employing gel filtr...