The mechanism of amyloid fibril growth from Φ-value analysis.

Amyloid fibrils are highly stable misfolded protein assemblies that play an important role in several neurodegenerative and systemic diseases. Although structural information of the amyloid state is now abundant, mechanistic details about the misfolding process remain elusive. Inspired by the Φ-value analysis of protein folding, we combined experiments and molecular simulations to resolve amino-acid contacts and determine the structure of the transition-state ensemble-the rate-limiting step-for fibril elongation of PI3K-SH3 amyloid fibrils.

Progress in understanding the infrared spectrum of the H2O-O2 dimer.

Spectra of the weakly bound H2O-O2 dimer are studied in the region of the H2O ν2 band using a tunable quantum cascade laser to probe a pulsed supersonic slit jet expansion. These are the first gas-phase infrared spectra of H2O-O2 and among only a few such results for O2-containing complexes. Almost 100 infrared lines are assigned based on the ground state combination differences from the microwave spectrum of H2O-O2.

Mycobacteria develop biofilms on airway epithelial cells and promote mucosal barrier disruption.

Tuberculosis displays several features commonly linked to biofilm-associated infections, including recurrence of infection and resistance to antibiotic treatment. The respiratory epithelium represents the first line of defense against pathogens such as (Mtb). Here, we use an air-liquid interface model of human primary bronchial epithelial cells (PBEC) to explore the capability of four species of mycobacteria (Mtb, (BCG), and ) to form biofilms on airway epithelial cells.

New Infrared Spectra of Acetylene-Water Dimers: First Determination of the Rotational Constant and Another -Dependent Anomaly.

Infrared spectra of acetylene-water complexes are studied in the regions of the HO ν bend (1600 cm) and the DO ν/ν stretches (2670-2808 cm), using tunable infrared sources to probe a pulsed supersonic slit jet expansion. In the HO bend region, there is a puzzling absence of = 0 transitions for CH-HO, while both = 0 and 1 are observed for CD-HO. This continues a pattern of "missing" states noted in previous infrared studies of acetylene-water.