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Papers by Craig Essenmacher

Journal of the American Chemical Society, May 1, 1992

Figures pertaining to the van't Hoff analyses of @-turn formation in the Pro-Ala, Pro-Gly, and Pr... more Figures pertaining to the van't Hoff analyses of @-turn formation in the Pro-Ala, Pro-Gly, and Pro-Val dipeptides (7 pages). Ordering information is given on any current masthead page.

Proceedings of the National Academy of Sciences of the United States of America, Sep 1, 1993

Time-resolved EPR studies with DNA photolyase: Excited-state FADHO abstracts an electron from Trp... more Time-resolved EPR studies with DNA photolyase: Excited-state FADHO abstracts an electron from Trp-306 to generate FADH-, the catalytically active form of the cofactor (ultraviolet/pyrimidine dimer/heavy isotopes)

Journal of the American Chemical Society, Feb 1, 1993

DNA photolyase photoconverts pyrimidine dimers to pyrimidines in the repair of UV-damaged DNA.' T... more DNA photolyase photoconverts pyrimidine dimers to pyrimidines in the repair of UV-damaged DNA.' The active form of the enzyme contains reduced flavin adenine dinucleotide, probably in its anion form (FADH-),2,3 as the direct photocatalyst. The repair reaction is initiated by electron transfer between the bound DNA substrate and the FADH-singlet excited statee2q4 Oneelectron oxidation of FADH-during enzyme isolation produces the neutral flavin semiquinone FADH', which is inactive in dimer repair but which can be photoactivated to produce functional e n~y m e .~ Optical data on this process suggest that photon absorption produces the FADH' doublet excited state, which in

Proceedings of the National Academy of Sciences, 1993

Photolyase repairs UV-induced cyclobutane-pyrimidine dimers in DNA by photoinduced electron trans... more Photolyase repairs UV-induced cyclobutane-pyrimidine dimers in DNA by photoinduced electron transfer. The enzyme isolated from Escherichia coli contains 5,10-methenyltetrahydrofolate, which functions as the light-harvesting chromophore, and fully reduced flavin adenine dinucleotide (FAD), which functions as the redox catalyst. During enzyme preparation, the flavin is oxidized to FADH0, which is catalytically inert. Illumination of the enzyme with 300- to 600-nm light converts the flavin to the fully reduced form in a reaction that involves photooxidation of an amino acid in the apoenzyme. The results of earlier optical studies had indicated that the redox-active amino acid in this photoactivation process was tryptophan. We have now used time-resolved electron paramagnetic resonance (EPR) spectroscopy to investigate the photoactivation reaction. Excitation of the flavin-radical-containing inactive enzyme produces a spin-polarized radical that we identify by 2H and 15N labeling as ori...

Journal of the American Chemical Society, 1992