Regulation of neural stem cell differentiation and brain development by MGAT5-mediated N-glycosylation.

Undifferentiated neural stem and progenitor cells (NSPCs) encounter extracellular signals that bind plasma membrane proteins and influence differentiation. Membrane proteins are regulated by N-linked glycosylation, making it possible that glycosylation plays a critical role in cell differentiation. We assessed enzymes that control N-glycosylation in NSPCs and found that loss of the enzyme responsible for generating β1,6-branched N-glycans, N-acetylglucosaminyltransferase V (MGAT5), led to specific changes in NSPC differentiation in vitro and in vivo.

On the protein (tyrosine)-chromophore (protonated Schiff base) coupling in bacteriorhodopsin.

The kinetics of formation of both the tyrosinate ion (from its absorption at 296 nm) and the deprotonated Schiff base (M412) (from its absorption at 404 nm) are studied simultaneously at different pH values (7-11) and temperatures (5-25 degrees C). Two formation rates are observed for M412 in agreement with previous observations. The slow one is dominant under physiological conditions and is found to be slightly faster than that for the tyrosinate formation.