Ubiquitin chain conformation regulates recognition and activity of interacting proteins.

Mechanisms of protein recognition have been extensively studied for single-domain proteins, but are less well characterized for dynamic multidomain systems. Ubiquitin chains represent a biologically important multidomain system that requires recognition by structurally diverse ubiquitin-interacting proteins. Ubiquitin chain conformations in isolation are often different from conformations observed in ubiquitin-interacting protein complexes, indicating either great dynamic flexibility or extensive chain remodelling upon binding.

Free-energy relationships for the interactions of tryptophan with phosphocholines.

In membrane proteins and peptides, tryptophan exhibits a marked tendency to occur in locations that correspond to the interfacial region of the lipid bilayer. The relative contributions of electrostatic, dipolar, hydrophobic and conformational effects on the interactions of tryptophan with lipids have been the subject of much speculation. In order to elucidate the fundamental properties of tryptophan-phosphocholine interactions in the absence of competing factors such as protein conformation and membrane perturbation, we have determined the binding characteristics of a homologous series of tryptophan analogues to 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) in deuterochloroform using NMR titrimetric approaches.

Folding study of Venus reveals a strong ion dependence of its yellow fluorescence under mildly acidic conditions.

Venus is a yellow fluorescent protein that has been developed for its fast chromophore maturation rate and bright yellow fluorescence that is relatively insensitive to changes in pH and ion concentrations. Here, we present a detailed study of the stability and folding of Venus in the pH range from 6.0 to 8.

The folding, stability and conformational dynamics of beta-barrel fluorescent proteins.

This critical review describes our current knowledge on the folding, stability and conformational dynamics of fluorescent proteins (FPs). The biophysical studies that have led to the elucidation of many of the key features of the complex energy landscape for folding for GFP and its variants are discussed. These illustrate some important issues surrounding how the large beta-barrel structure forms, and will be of interest to the protein folding community.

Untangling the folding mechanism of the 5(2)-knotted protein UCH-L3.

Proteins possessing deeply embedded topological knots in their structure add a stimulating new challenge to the already complex protein-folding problem. The most complicated knotted topology observed to date belongs to the human enzyme ubiquitin C-terminal hydrolase UCH-L3, which is an integral part of the ubiquitin-proteasome system. The structure of UCH-L3 contains five distinct crossings of its polypeptide chain, and it adopts a 5(2)-knotted topology, making it a fascinating target for folding studies.