The two major forms of Shiga toxin, Stx1 and Stx2, use the glycolipid globotriaosylceramide (Gb3) as their cellular receptor. Stx1 primarily recognizes the Pk-trisaccharide portion and has three Pk binding sites per B monomer. The Stx2a subtype requires glycolipid residues in addition to Pk. We synthesized analogs of Pk to examine the binding preferences of Stx1 and Stx2 subtypes a to d. Furthe...

Boar spermatozoa contain isoforms of both glyceraldehyde 3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12) and pyruvate kinase (PK, EC 2.7.1.40). The sperm-specific forms, GAPDH-S and PK-S, are tightly bound to cell structures. By immunofluorescence microscopy GAPDH-S and PK-S were localised in the principal piece of the boar sperm flagellum as well as in the acrosomal region of the sperm head and...

Accurate computational methods of determining protein and nucleic acid pK(a) values are vital to understanding pH-dependent processes in biological systems. In this article, we use the recently developed method constant pH molecular dynamics (CPHMD) to explore the calculation of highly perturbed pK(a) values in variants of staphylococcal nuclease (SNase). Simulations were performed using the re...

Previous studies have shown that the herpes simplex virus type 2 protein kinase ICP10 PK activates the Ras/MEK/MAPK pathway in nonneuronal cells. Here we report that ectopically expressed ICP10 PK has anti-apoptotic activity in various paradigms of neuronal cell death. Neuronally differentiated PC12 cells and primary murine hippocampal cultures transfected with an expression vector for ICP10 PK...

Continuing our studies on cGMP in growing yeast we detected a particulate cGMP dependent protein kinase (Pk-G), which was solubilized by detergents and NaCl. It achieves maximum activity at 25 degrees C and pH = 6.8, high concentrations of substrate proteins or cGMP produce saturation. Casein and histones are appropriate substrates, phosphatase-pretreated histone H-2a provokes outstandingly hig...

Tuberculosis (TB) kills more people than any other infectious disease. Challenges for developing better treatments include the complex pathology due to within-host immune dynamics, interpatient variability in disease severity and drug pharmacokinetics-pharmacodynamics (PK-PD), growing emergence of resistance. Model-informed development using quantitative translational pharmacology has become in...

DNA-dependent protein kinase (DNA-PK) plays a critical role in DNA damage repair, especially in non-homologous end-joining repair of double-strand breaks such as those formed by ionizing radiation (IR) in the course of radiation therapy. Regulation of DNA-PK involves multisite phosphorylation but this is incompletely understood and little is known about protein phosphatases relative to DNA-PK. ...

Protein kinase C (PK-C) was demonstrated in human erythrocytes using the exogenous substrate histone H1. The enzyme was dependent on the simultaneous presence of micromolar Ca2+ and phosphatidylserine. The Ca2+ requirement was reduced in the presence of the tumor promoter 12-O-tetradecanoylphorbol 13-acetate (TPA). Activity was normally recovered in cytoplasmic extracts, but treatment of intact...

The plasma zymogens factor XI (fXI) and prekallikrein (PK) are activated by factor XIIa (fXIIa) during contact activation. Polyanions such as DNA and RNA may contribute to thrombosis and inflammation partly by enhancing PK and fXI activation. We examined PK and fXI activation in the presence of nucleic acids, and determine the effects of the cofactor high molecular weight kininogen (HK) on the ...