Ultra-rapid Electrophilic Cysteine Arylation.

Rapid bond-forming reactions are crucial for efficient bioconjugation. We describe a simple and practical strategy for facilitating ultra-rapid electrophilic cysteine arylation. Using a variety of sulfone-activated pyridinium salts, this uncatalyzed reaction proceeds with exceptionally high rate constants, ranging from 9800 to 320,000 M·s, in pH 7.

Rapid Electrophilic Cysteine Arylation with Pyridinium Salts.

Here, we present a series of fluorinated cationic reagents that enable rapid arylation of cysteine under mild conditions compatible with proteins and peptides. The highly polarized C-F bond and attractive nucleophile-electrophile Coulombic interactions substantially accelerate cysteine arylation, leading to unusually high rate constants on the order of 100 M·s and allowing for equimolar labeling of substrates at micromolar concentrations. The synthetic modularity of this approach promotes the direct coupling of structurally diverse phenol-containing functional motifs to cysteine residues of biomacromolecules with high efficiency.

Cross-α/β polymorphism of PSMα3 fibrils.

The formation of ordered cross-β amyloid protein aggregates is associated with a variety of human disorders. While conventional infrared methods serve as sensitive reporters of the presence of these amyloids, the recently discovered amyloid secondary structure of cross-α fibrils presents new questions and challenges. Herein, we report results using Fourier transform infrared spectroscopy and two-dimensional infrared spectroscopy to monitor the aggregation of one such cross-α-forming peptide, phenol soluble modulin alpha 3 (PSMα3).

Mechanisms Underlying Long-Term Synaptic Zinc Plasticity at Mouse Dorsal Cochlear Nucleus Glutamatergic Synapses.

In many brain areas, such as the neocortex, limbic structures, and auditory brainstem, synaptic zinc is released from presynaptic terminals to modulate neurotransmission. As such, synaptic zinc signaling modulates sensory processing and enhances acuity for discrimination of different sensory stimuli. Whereas sensory experience causes long-term changes in synaptic zinc signaling, the mechanisms underlying this long-term synaptic zinc plasticity remain unknown.