Optimizing storage stability of lyophilized recombinant human interleukin-11 with disaccharide/hydroxyethyl starch mixtures.

Optimal storage stability of a protein in a dry formulation depends on the storage temperature relative to the glass transition temperature (T(g)) of the dried formulation and the structure of the dried protein. We tested the hypothesis that optimizing both protein structure and T(g)--by freeze-drying recombinant human interleukin-11 (rhIL-11) with mixtures of disaccharides and hydroxyethyl starch (HES)--would result in increased storage stability compared with the protein lyophilized with either disaccharide or hydroxyethyl starch alone. The secondary structure of the protein in the dried solid was analyzed immediately after lyophilization and after storage at elevated temperatures by infrared spectroscopy.

The use of fluorescence resonance energy transfer to monitor dynamic changes of lipid-DNA interactions during lipoplex formation.

Fluorescence resonance energy transfer (FRET) was used to monitor interactions between Cy3-labeled plasmid DNA and NBD-labeled cationic liposomes. FRET data show that binding of cationic liposomes to DNA occurs immediately upon mixing (within 1 min), but FRET efficiencies do not stabilize for 1-5 h. The time allowed for complex formation has effects on in vitro luciferase transfection efficiencies of DOPE-based lipoplexes; i.

Oxidative dimer formation is the critical rate-limiting step for Parkinson's disease alpha-synuclein fibrillogenesis.

Intraneuronal deposition of alpha-synuclein as fibrils and oxidative stress are both implicated in the pathogenesis of Parkinson's disease. We found that the critical rate-limiting step in nucleation of alpha-synuclein fibrils under physiological conditions is the oxidative formation and accumulation of a dimeric, dityrosine cross-linked prenucleus. Dimer formation is accelerated for the pathogenic A30P and A53T mutant alpha-synucleins, because of their greater propensity to self-interact, which is reflected in the smaller values of the osmotic second virial coefficient compared to that of wild-type synuclein.