Effects of osmolytes on protein-solvent interactions in crowded environment: Analyzing the effect of TMAO on proteins in crowded solutions.

We analyzed the effect of a natural osmolyte, trimethylamine N-oxide (TMAO), on structural properties and conformational stabilities of several proteins under macromolecular crowding conditions by a set of biophysical techniques. We also used the solvent interaction analysis method to look at the peculiarities of the TMAO-protein interactions under crowded conditions. To this end, we analyzed the partitioning of these proteins in TMAO-free and TMAO-containing aqueous two-phase systems (ATPSs).

Influence of serum proteins on conformation of prostate-specific antigen.

Partition behavior of prostate-specific antigen (PSA) was studied in aqueous Dextran-Ficoll two-phase system. It was found that the partitioning of PSA changed in the presence of other proteins, in particular, bovine serum albumin, human serum albumin, human transferrin, and human gamma-globulin. The partition coefficient of PSA in mixtures with increasing amounts of these proteins decreased along the S-shaped curve and dropped to essentially the same value at the 10(4)-10(5) protein: PSA molar ratio.

Prostate-specific antigen/solvent interaction analysis: a preliminary evaluation of a new assay concept for detecting prostate cancer using urinary samples.

Objective: To provide preliminary clinical performance evaluation of a novel prostate cancer (CaP) assay, prostate-specific antigen/solvent interaction analysis (PSA/SIA) that focused on changes to the structure of PSA.

Methods: Two-hundred twenty-two men undergoing prostate biopsy for accepted clinical criteria at 3 sites (University Hospitals Case Medical Center in Cleveland, Cleveland Clinic, and Veterans Administration Boston Healthcare System) were enrolled in institutional review board-approved study. Before transrectal ultrasound-guided biopsy, patients received digital rectal examination with systematic prostate massage followed by collection of urine.

Molecular mechanism of kNBC1-carbonic anhydrase II interaction in proximal tubule cells.

We have recently shown that carbonic anhydrase II (CAII) binds in vitro to the C-terminus of the electrogenic sodium bicarbonate cotransporter kNBC1 (kNBC1-ct). In the present study we determined the molecular mechanisms for the interaction between the two proteins and whether kNBC1 and CAII form a transport metabolon in vivo wherein bicarbonate is transferred from CAII directly to the cotransporter. Various residues in the C-terminus of kNBC1 were mutated and the effect of these mutations on both the magnitude of CAII binding and the function of kNBC1 expressed in mPCT cells was determined.

Phosphorylation-induced modulation of pNBC1 function: distinct roles for the amino- and carboxy-termini.

The human NBC1 (SLC4A4) gene encodes the electrogenic sodium bicarbonate cotransporters kNBC1 and pNBC1, which are highly expressed in the kidney and pancreas, respectively. The HCO3-:Na+ stoichiometry of these cotransporters is an important determinant of the direction of ion flux. Recently we showed in a mouse proximal tubule (mPCT) cell line expressing kNBC1, that 8-Br-cAMP shifts the stoichiometry of the cotransporter from 3:1 to 2:1 via protein kinase A (PKA)-dependent phosphorylation of Ser982.