Our result shows that the Nxnl1 gene, through the thioredoxin RdCVFL, is part of an endogenous defense mechanism against photooxidative stress that is likely of great importance for human vision. (C) 2015 Elsevier Inc. All rights reserved.”
“beta-Crystallins are the major structural proteins in mammalian lens, and their stability is critical in maintaining the transparency and refraction index of the lens. Among the seven beta-crystallins,
beta A3-crystallin and beta B1-crystallin, an acidic and a basic beta-crystallin, respectively, can form heteromers in vivo. However, the physiological roles of the heteromer have not been fully elucidated. In this research, we studied whether the basic beta-crystallin selleck kinase inhibitor selleck facilitates the folding of acidic beta-crystallin. Equilibrium folding studies revealed that the beta A3-crystallin and beta B1-crystallin homomers and the beta A3/beta B1-crystallin heteromer all undergo similar
five-state folding pathways which include one dimeric and two monomeric intermediates. beta A3-Crystallin was found to be the most unstable among the three proteins, and the transition curve of beta A3/beta B1-crystallin was close to that of beta B1-crystallin. The dimeric intermediate may be a critical determinant in the aggregation process and thus is crucial to the lifelong stability of the beta-crystallins. A comparison of the Gibbs free energy of the equilibrium folding suggested that the formation of heteromer contributed to the stabilization of the dimer interface. On the other hand, beta A3-crystallin, the only protein whose refolding is challenged by serious aggregation, can be protected by beta B1-crystallin in a dose-dependent manner during the kinetic CUDC-907 co-refolding. However, the protection is not observed in the presence of the pre-existed well-folded beta B1-crystallin. These findings suggested that the formation of beta-crystallin heteromers not only stabilizes the unstable acidic beta-crystallin but also protects them against aggregation during refolding from the stress-denatured states.”
“With increasing protein concentrations,
therapeutic protein formulations are increasingly demonstrating significant deviations from ideal dilute solution behavior due to protein-protein interactions. These interactions lead to unique biophysical challenges in the administration of biopharmaceuticals including high apparent viscosity and viscoelasticity as well as challenges in maintaining the physical stability of proteins in solution. Here, we describe a straightforward analytical method to calculate the complex modulus and viscosity of high concentration protein solutions from measurements made using quartz crystal microbalance with dissipation monitoring (QCM-D). Further, this methodology was used to investigate the dependence of the storage and loss moduli (G’ and G ”, respectively) of a humanized monoclonal antibody solution on solution pH.