Site-Specific Detection and Characterization of Ubiquitin Carbamylation.

The physiological consequences of varying in vivo CO levels point to a general mechanism for CO to influence cellular homeostasis beyond regulating pH. Aside from a few instances where CO has been observed to cause post-translational protein modification, by forming long-lived carbamates, little is known about how transitory and ubiquitous carbamylation events could induce a physiological response. Ubiquitin is a versatile protein involved in a multitude of cellular signaling pathways as polymeric chains of various lengths formed through one of the seven lysines or N-terminal amine.

Anomalous Properties of Lys Residues Buried in the Hydrophobic Interior of a Protein Revealed with N-Detect NMR Spectroscopy.

Ionizable residues buried in hydrophobic environments in proteins are essential for many fundamental biochemical processes. These residues titrate with anomalous pK values that are challenging to reproduce with structure-based calculations owing to the conformational reorganization coupled to their ionization. Detailed characterization of this conformational reorganization is of interest; unfortunately, the properties of buried Lys residues are difficult to study experimentally.

Potent and specific peptide inhibitors of human pro-survival protein Bcl-xL.

The Bcl-2 family of proteins plays a critical role regulating apoptosis, and pro-survival Bcl-2 family members are important therapeutic targets due to their overexpression in different cancers. Pro-apoptotic Bcl-2 homology 3 (BH3)-only proteins antagonize pro-survival Bcl-2 protein functions by binding directly to them, and a sub-class of BH3-only proteins termed sensitizers can initiate apoptosis via this mechanism in response to diverse signals. The five pro-survival proteins Bcl-xL, Mcl-1, Bcl-2, Bcl-w and Bfl-1 differ in their binding preferences, with Bcl-xL, Bcl-2 and Bcl-w sharing similar interaction profiles for many natural sensitizers and small molecules.

Intragenic suppressing mutations correct the folding and intracellular traffic of misfolded mutants of Yor1p, a eukaryotic drug transporter.

ATP-binding cassette (ABC) transporters play pivotal physiological roles in substrate transport across membranes, and defective assembly of these proteins can cause severe disease associated with improper drug or ion flux. The yeast protein Yor1p is a useful model to study the biogenesis of ABC transporters; deletion of a phenylalanine residue in the first nucleotide-binding domain (NBD1) causes misassembly and retention in the endoplasmic reticulum (ER) of the resulting protein Yor1p-ΔF670, similar to the predominant disease-causing allele in humans, CFTR-ΔF508. Here we describe two novel Yor1p mutants, G278R and I1084P, which fail to assemble and traffic similar to Yor1p-ΔF670.