TOP - The RNA from stem-loop SL3 in the packaging signal domain of HIV-1 RNA.

BOTTOM - The complex between SL3 RNA and the NCp7 nucleocapsid protein from HIV-1. Click the link to Prof. Borer's web page for more details. The structure of the SL3-NC complex was determined by Mike Summers' group at the University of Maryland, Baltimore County in collaboration with our lab.

TOP - The light harvesting protein, bacteriorhodopsin, depends on conformational changes in the retinal chromophore, shown in pink. Changes in the environment of the retinal in different stages of the photocycle are of considerable interest. Step-scan time-resolved FTIR spectra are used to examine dynamics of protein conformational changes.

BOTTOM - Click this picture for a slide show from the Braiman lab. The show features bacteriorhodopsin and infrared spectroscopy.

TOP - We're interested in mapping the folded conformations of RNA using techniques such as quantitative footprinting. The major packaging domain of HIV-1 may fold in a manner similar to the low free energy form predicted by the Borer group.

BOTTOM - The gel pattern shows how the RNase T1 cutting pattern changes upon increasing the concentration of paromomycin. The cleavage pattern helps us to evaluate alternative folds.

Evolutionary trees are usually calibrated in genetic distance. New results allow us to calibrate the tree in units of time, as illustrated here.

This is a close-up view of the SL3-NCp7 complex from Summers and Borer, showing details of the stacking of G318 on Trp37. This quenches the fluorescence of the tryptophan and is the basis for a sensitive assay for binding to the protein.

The picture illustrates a DNA nucleoside with site-specific labeling of C1, C3, and C5 with C-13. Staggered labeling like this should make it easier to interpret NMR relaxation measurements to extract information on internal and overall motion.

An image of opacified vasculature of a rat obtained using ultra-fast Laser Produced Plasma (LPP) x-ray source in the Dual Energy Subtraction Angiography (DESA) mode. Up till now it was only possible using a synchrotron (>$100M) now we can do it in a clinic or a small lab using $1M device, we hope to make it cheaper in the future. The image was obtained in the INRS laboratory (U. of Quebec, Varennes) in the framework of my NHBLI/ NIH grant by my subcontractor Dr. Jean-Claude Kieffer.

TOP - Protein Disulfide Isomerase (PDI) catalyzes the rearrangement of improperly folded proteins by reducing their disulfides, allowing them to refold, then reforming the disulfides.

BOTTOM - The oxidized (blue) and reduced (pink) conformations of PDI are almost identical except for a single disulfide - dithiol. Small molecules might catalyze the disulfide bond rearrangement of proteins, a topic of work in our lab.

Protein folding is a multistep process. We focus on characterizing folding intermediates. An important model system is myoglobin, illustrated at left, with the alpha-helix segments that fold/unfold in a coordinated fashion colored the same. Our work includes NMR spectroscopy as well as methods in molecular biology, biochemistry, and biophysics.

An EM cross section of a flagellar axoneme from Chlamydomonas reinhardtii.

Localization of conserved nucleotides in domain 1 of the RNase MRP structure. Only domain 1 is shown in space filling. Nucleotides from domain 2, are represented as a backbone only. Individual nucleotides conserved in all known RNase MRP RNAs are shown in yellow. Uridine 88 in is colored red for orientation.