Reversible beta-pleated sheet formation of a phosphorylated synthetic tau peptide.

Serine416 of human tau protein is believed to be phosphorylated in Alzheimer neurofibrillary tangles. We synthesized a fragment of tau, consisting of amino acids 408-421 in both non-phosphorylated and serine416-phosphorylated forms. Circular dichroism in a trifluoroethanol-water mixture indicated a beta-turn----beta-pleated sheet conformational transition upon phosphorylation.

Solid-phase synthesis of phosphopeptides.

We report the solid-phase synthesis of peptides containing O-phosphoserine. Coupling was with commercially available Fmoc-amino acid pentafluorophenyl esters, with base used at each cycle to cleave Fmoc. Phosphorylation of those serine residues left unprotected on the peptide-resin was achieved with dibenzylphosphochloridate, and finally trifluoroacetic acid was used to remove side-chain protecting groups (including the benzyl groups used for the phosphate), and to cleave the peptide from the resin in the same step.

Taurine levels in discrete brain nuclei of rats.

Concentrations of taurine have been measured in 44 microdissected rat brain nuclei or areas. Taurine is ubiquitously present and distributed unevenly in the rat brain: the ratio of the highest (pyriform cortex) to lowest (midbrain reticular formation) concentrations is 4.7:1.