SNARE complexes mediate membrane fusion in the endomembrane system. They consist of coiled-coil bundles of four helices designated as Qa, Qb, Qc and R. A critical intermediate in the fusion pathway is the trans-SNARE complex generated by the assembly of SNAREs residing in opposing membranes. Mechanistic details of trans-SNARE complex formation and topology in a physiological system remain large...

Methanol dimer (CD3OH)2 ion–molecule reaction is initialized by VUV ~vacuum ultraviolet! laser photoionization. The proton and deuteron transfers are the dominant reactions. The relative probabilities of deuteron transfer from the methyl group and proton from the hydroxyl group were measured as a function of VUV photon energy between 10.91 to 10.49 eV. According to those results, the probabilit...

Exocytosis from synaptic vesicles is driven by stepwise formation of a tight alpha-helical complex between the fusing membranes. The complex is composed of the three SNAREs: synaptobrevin 2, SNAP-25, and syntaxin 1a. An important step in complex formation is fast binding of vesicular synaptobrevin to the preformed syntaxin 1.SNAP-25 dimer. Exactly how this step relates to neurotransmitter relea...

Helicase-nuclease systems dedicated to DNA end resection in preparation for homologous recombination (HR) are present in all kingdoms of life. In thermophilic archaea, the HerA helicase and NurA nuclease cooperate with the highly conserved Mre11 and Rad50 proteins during HR-dependent DNA repair. Here we show that HerA and NurA must interact in a complex with specific subunit stoichiometry to pr...

The Central glycolytic genes Repressor (CggR) from Bacillus subtilis belongs to the SorC family of transcription factors that control major carbohydrate metabolic pathways. Recent studies have shown that CggR binds as a tetramer to its tandem operator DNA sequences and that the inducer metabolite, fructose 1,6-bisphosphate (FBP), reduces the binding cooperativity of the CggR/DNA complex. Here, ...