title: Two-dimensional infrared spectroscopy of azido-nicotinamide adenine dinucleotide in water.
abstract: Mid-IR active analogs of enzyme cofactors have the potential to be important spectroscopic reporters of enzyme active site dynamics. Azido-nicotinamide adenine dinucleotide (NAD(+)), which has been recently synthesized in our laboratory, is a mid-IR active analog of NAD(+), a ubiquitous redox cofactor in biology. In this study, we measure the frequency-frequency time correlation function for the antisymmetric stretching vibration of the azido group of azido-NAD(+) in water. Our results are consistent with previous studies of pseudohalides in water. We conclude that azido-NAD(+) is sensitive to local environmental fluctuations, which, in water, are dominated by hydrogen-bond dynamics of the water molecules around the probe. Our results demonstrate the potential of azido-NAD(+) as a vibrational probe and illustrate the potential of substituted NAD(+)-analogs as reporters of local structural dynamics that could be used for studies of protein dynamics in NAD-dependent enzymes.
authors.affiliation: Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, USA.
authors.forename: Samrat
authors.initials: S
authors.lastname: Dutta
authors.forename: William
authors.initials: W
authors.lastname: Rock
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Cook
authors.forename: Amnon
authors.initials: A
authors.lastname: Kohen
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Cheatum
mesh_terms: D001386:Azides / Q000737:chemistry*; D009243:NAD / Q000737:chemistry*; D013055:Spectrophotometry, Infrared / Q000379:methods; D014867:Water / Q000737:chemistry
chemical_list: D001386:Azides; D014867:Water; D009243:NAD