@inbook {1679, title = {New Tools for Life Science Research Based on Fiber-Optic-Linked Raman and Resonance Raman Spectroscopy}, booktitle = {New Approaches in Biomedical Spectroscopy}, series = {Acs Symposium Series}, volume = {963}, year = {2007}, note = {ISI Document Delivery No.: BKS87Times Cited: 2Cited Reference Count: 17Blades, M. W. Schulze, H. G. Konorov, S. O. Addison, C. J. Jirasek, A. I. Turner, R. F. B.Proceedings PaperSymposium on Approaches in Biomedical Spectroscopy2005Honolulu, HIAmer Chem Soc1155 SIXTEENTH ST NW, WASHINGTON, DC 20036 USA}, pages = {1-13}, publisher = {Amer Chemical Soc}, organization = {Amer Chemical Soc}, address = {Washington}, abstract = {Fiber-optic probes can exploit a favorable excitation radiation distribution within the sample that allows the use of higher laser power levels which, in turn, can yield a higher signal-to-noise ratio (SNR) for a given experiment without increasing the risk of analyte photo-damage. We have developed specialized fiber-optic probes for ultraviolet resonance Raman spectroscopy (UVRRS) that offer several advantages over conventional excitation/collection methods used for UVRRS. These probes are ideally suited for UVRRS studies involving biopolymers and small bio-molecules, in both native (e.g. physiological) and non-native (e.g. anoxic) solution environments. We have also developed novel probes based on hollow-core photonic band-gap fibers that virtually eliminate the generation of silica Raman scattering within the excitation fiber which often limits the utility of fiber-optic Raman probes in turbid media or near surfaces. These probes may offer advantages for some biomedical applications.}, keywords = {1, 2-DIOXYGENASE, PHOTONIC-CRYSTAL FIBER, PICOSECOND PULSES}, isbn = {0097-6156978-0-8412-7437-2}, url = {://000269122900001}, author = {Blades, M. W. and Schulze, H. G. and Konorov, S. O. and Addison, C. J. and Jirasek, A. I. and Turner, R. F. B.}, editor = {Kneipp, K. and Aroca, R. and Kneipp, H. and Wen trupByrne, E.} } @inbook {1679, title = {New Tools for Life Science Research Based on Fiber-Optic-Linked Raman and Resonance Raman Spectroscopy}, booktitle = {New Approaches in Biomedical Spectroscopy}, series = {Acs Symposium Series}, volume = {963}, year = {2007}, note = {ISI Document Delivery No.: BKS87Times Cited: 2Cited Reference Count: 17Blades, M. W. Schulze, H. G. Konorov, S. O. Addison, C. J. Jirasek, A. I. Turner, R. F. B.Proceedings PaperSymposium on Approaches in Biomedical Spectroscopy2005Honolulu, HIAmer Chem Soc1155 SIXTEENTH ST NW, WASHINGTON, DC 20036 USA}, pages = {1-13}, publisher = {Amer Chemical Soc}, organization = {Amer Chemical Soc}, address = {Washington}, abstract = {Fiber-optic probes can exploit a favorable excitation radiation distribution within the sample that allows the use of higher laser power levels which, in turn, can yield a higher signal-to-noise ratio (SNR) for a given experiment without increasing the risk of analyte photo-damage. We have developed specialized fiber-optic probes for ultraviolet resonance Raman spectroscopy (UVRRS) that offer several advantages over conventional excitation/collection methods used for UVRRS. These probes are ideally suited for UVRRS studies involving biopolymers and small bio-molecules, in both native (e.g. physiological) and non-native (e.g. anoxic) solution environments. We have also developed novel probes based on hollow-core photonic band-gap fibers that virtually eliminate the generation of silica Raman scattering within the excitation fiber which often limits the utility of fiber-optic Raman probes in turbid media or near surfaces. These probes may offer advantages for some biomedical applications.}, keywords = {1, 2-DIOXYGENASE, PHOTONIC-CRYSTAL FIBER, PICOSECOND PULSES}, isbn = {0097-6156978-0-8412-7437-2}, url = {://000269122900001}, author = {Blades, M. W. and Schulze, H. G. and Konorov, S. O. and Addison, C. J. and Jirasek, A. I. and Turner, R. F. B.}, editor = {Kneipp, K. and Aroca, R. and Kneipp, H. and Wen trupByrne, E.} } @article {1135, title = {Spectroscopic studies of the anaerobic enzyme - Substrate complex of catechol 1,2-dioxygenase}, journal = {Journal of the American Chemical Society}, volume = {127}, number = {48}, year = {2005}, note = {ISI Document Delivery No.: 990QVTimes Cited: 17Cited Reference Count: 86}, month = {Dec}, pages = {16882-16891}, type = {Article}, abstract = {The basis of the respective regiospecificities of intradiol and extradiol dioxygenase is poorly understood and may be linked to the protonation state of the bidentate-bound catechol in the enzyme/ substrate complex. Previous ultraviolet resonance Raman (UVRR) and UV-visible (UV-vis) difference spectroscopic studies demonstrated that, in extradiol dioxygenases, the catechol is bound to the Fe(II) as a monoanion. In this study, we use the same approaches to demonstrate that, in catechol 1,2-dioxygenase (C120), an intradiol enzyme, the catechol binds to the Fe(III) as a dianion. Specifically, features at 290 nm and 1550 cm(-1) in the UV-vis and UVRR difference spectra, respectively, are assigned to dianionic catechol based on spectra of the model compound, ferric tris(catecholate). The UVRR spectroscopic band assignments are corroborated by density functional theory (DFT) calculations. In addition, negative features at 240 nm in UV-vis difference spectra and at 1600, 1210, and 1175 cm(-1) in UVRR difference spectra match those of a tyrosinate model compound, consistent with protonation of the axial tyrosinate ligand when it is displaced from the ferric ion coordination sphere upon substrate binding. The DFT calculations ascribe the asymmetry of the bound dianionic substrate to the trans donor effect of an equatorially ligated tyrosinate ligand. In addition, the computations suggest that trans donation from the tyrosinate ligand may facilitate charge transfer from the substrate to yield the iron-bound semiquinone transition state, which is capable of reacting with dioxygen. In illustrating the importance of ligand trans effects in a biological system, the current study demonstrates the power of combining difference UVRR and optical spectroscopies to probe metal ligation in solution.}, keywords = {1, 2, 2-DIOXYGENASE, 3-DIHYDROXYBIPHENYL, 4-DIOXYGENASE, ACTIVE-SITE, CRYSTAL-STRUCTURE, DENSITY-FUNCTIONAL THEORY, EXTRADIOL DIOXYGENASES, IRON-TRANSPORT COMPOUNDS, ISOTOPIC-SUBSTITUTION SHIFTS, PROTOCATECHUATE 3, PSEUDOMONAS-ARVILLA C-1, RESONANCE RAMAN-SPECTROSCOPY}, isbn = {0002-7863}, url = {://000233759200038}, author = {Horsman, G. P. and Jirasek, A. and Vaillancourt, F. H. and Barbosa, C. J. and Jarzecki, A. A. and Xu, C. L. and Mekmouche, Y. and Spiro, T. G. and Lipscomb, J. D. and Blades, M. W. and Turner, R. F. B. and Eltis, L. D.} } @article {1135, title = {Spectroscopic studies of the anaerobic enzyme - Substrate complex of catechol 1,2-dioxygenase}, journal = {Journal of the American Chemical Society}, volume = {127}, number = {48}, year = {2005}, note = {ISI Document Delivery No.: 990QVTimes Cited: 17Cited Reference Count: 86}, month = {Dec}, pages = {16882-16891}, type = {Article}, abstract = {The basis of the respective regiospecificities of intradiol and extradiol dioxygenase is poorly understood and may be linked to the protonation state of the bidentate-bound catechol in the enzyme/ substrate complex. Previous ultraviolet resonance Raman (UVRR) and UV-visible (UV-vis) difference spectroscopic studies demonstrated that, in extradiol dioxygenases, the catechol is bound to the Fe(II) as a monoanion. In this study, we use the same approaches to demonstrate that, in catechol 1,2-dioxygenase (C120), an intradiol enzyme, the catechol binds to the Fe(III) as a dianion. Specifically, features at 290 nm and 1550 cm(-1) in the UV-vis and UVRR difference spectra, respectively, are assigned to dianionic catechol based on spectra of the model compound, ferric tris(catecholate). The UVRR spectroscopic band assignments are corroborated by density functional theory (DFT) calculations. In addition, negative features at 240 nm in UV-vis difference spectra and at 1600, 1210, and 1175 cm(-1) in UVRR difference spectra match those of a tyrosinate model compound, consistent with protonation of the axial tyrosinate ligand when it is displaced from the ferric ion coordination sphere upon substrate binding. The DFT calculations ascribe the asymmetry of the bound dianionic substrate to the trans donor effect of an equatorially ligated tyrosinate ligand. In addition, the computations suggest that trans donation from the tyrosinate ligand may facilitate charge transfer from the substrate to yield the iron-bound semiquinone transition state, which is capable of reacting with dioxygen. In illustrating the importance of ligand trans effects in a biological system, the current study demonstrates the power of combining difference UVRR and optical spectroscopies to probe metal ligation in solution.}, keywords = {1, 2, 2-DIOXYGENASE, 3-DIHYDROXYBIPHENYL, 4-DIOXYGENASE, ACTIVE-SITE, CRYSTAL-STRUCTURE, DENSITY-FUNCTIONAL THEORY, EXTRADIOL DIOXYGENASES, IRON-TRANSPORT COMPOUNDS, ISOTOPIC-SUBSTITUTION SHIFTS, PROTOCATECHUATE 3, PSEUDOMONAS-ARVILLA C-1, RESONANCE RAMAN-SPECTROSCOPY}, isbn = {0002-7863}, url = {://000233759200038}, author = {Horsman, G. P. and Jirasek, A. and Vaillancourt, F. H. and Barbosa, C. J. and Jarzecki, A. A. and Xu, C. L. and Mekmouche, Y. and Spiro, T. G. and Lipscomb, J. D. and Blades, M. W. and Turner, R. F. B. and Eltis, L. D.} }