2D-IR study of a photoswitchable isotope-labeled alpha-helix.

2D-IR Study of a Photoswitchable Isotope-Labeled α-Helix

Alpha-helix formation in a photoswitchable peptide tracked from picoseconds to microseconds by time-resolved IR spectroscopy.

Photo-triggered alpha-helix formation of a 16-residue peptide featuring a built-in conformational photoswitch is monitored by time-resolved IR spectroscopy. An experimental approach with 2-ps time resolution and a scanning range up to 30 micros is used to cover all time scales of the peptide dynamics. Experiments are carried out at different temperatures between 281 and 322 K. We observe single...

Effect of hydrophobic surfactant proteins SP-B and SP-C on phospholipid monolayers. Protein structure studied using 2D IR and beta correlation analysis.

We have applied two-dimensional infrared (2D IR) and betanu correlation spectroscopy to in-situ IR spectroscopy of pulmonary surfactant proteins SP-B and SP-C in lipid-protein monolayers at the air-water interface. For both SP-B and SP-C, a statistical windowed autocorrelation method identified two separate surface pressure regions that contained maximum amide I intensity changes: 4-25 mN/m and...

Alpha-Helix folding in the presence of structural constraints.

We have investigated the site-specific folding kinetics of a photoswitchable cross-linked alpha-helical peptide by using single (13)C = (18)O isotope labeling together with time-resolved IR spectroscopy. We observe that the folding times differ from site to site by a factor of eight at low temperatures (6 degrees C), whereas at high temperatures (45 degrees C), the spread is considerably smalle...

Strategies for extracting structural information from 2D IR spectroscopy of amyloid: application to islet amyloid polypeptide.

The 37-residue human islet amyloid polypeptide (hIAPP or amylin) self-assembles into fibers, the assembly of which has been associated with the disease mechanism of type II diabetes. Infrared spectroscopy in conjunction with isotope labeling is proving to be a powerful tool for studying the aggregation process of hIAPP and other amyloid forming proteins with residue specific structure and kinet...