Common intermediates and kinetics, but different energetics, in the assembly of SNARE proteins.

Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) are evolutionarily conserved machines that couple their folding/assembly to membrane fusion. However, it is unclear how these processes are regulated and function. To determine these mechanisms, we characterized the folding energy and kinetics of four representative SNARE complexes at a single-molecule level using high-resolution optical tweezers.

Beta-peptide bundles with fluorous cores.

We reported recently that certain beta-peptides self-assemble spontaneously into cooperatively folded bundles whose kinetic and thermodynamic metrics mirror those of natural helix bundle proteins. The structures of four such beta-peptide bundles are known in atomic detail. These structures reveal a solvent-sequestered, hydrophobic core stabilized by a unique arrangement of leucine side chains and backbone methylene groups.