| AUTHOR |
TITLE |
Hurley, J. K.,
Fillat, M. F.,
Gomez-Moreno, C.,
Tollin, G. |
Electrostatic and Hydrophobic Interactions during Complex Formation and Electron Transfer in the Ferredoxin/Ferredoxin:NADP+ Reductase System from Anabaena
Journal of the American Chemical Society; 1996; 118(24); 5526-5531. (Article) |
Materials and Methods
UV-vis absorbance spectra were measured with an OLIS (Bogart, GA) modified Cary-15 spectrophotometer. Fd concentrations were determined using an extinction coefficient of 9700 M-1 cm-1 at 422 nm,13 and FNR concentrations were calculated using an extinction coefficient of 9400 M-1 cm-1 at 459 nm.
When needed, Ar was blown over the sample surface to remove traces of O2 added upon subsequent introduction of protein or NaCl to the sample. Generally 4-10 flashes were averaged. Kinetic traces were well fit by a single exponential, and were analyzed by a computer fitting procedure (Kinfit, OLIS Co., Bogart, GA). dRf was synthesized as described previously. |
Rosell, F. I.,
Ferrer, J. C.,
Mauk, A. G. |
Proton-Linked Protein Conformational Switching: Definition of the Alkaline Conformational Transition of Yeast Iso-1-ferricytochrome c
Journal of the American Chemical Society; 1998; 120(44); 11234-11245. |
Experimental Procedures
Electronic Absorption Spectroscopy
Electronic spectra were obtained with a Cary Model 219 spectrophotometer that was interfaced to a microcomputer (OLIS, Bogart, GA) and fitted with a jacketed cuvette holder that was maintained at 25 ˚C with a thermostated, circulating water bath (Lauda Model RMS6). |
Twitchett, M. B.,
Ferrer, J. C.,
Siddarth, P.,
Mauk, A. G. |
Intramolecular Electron Transfer Kinetics of a Synthetic Flavocytochrome c
Journal of the American Chemical Society; 1997; 119(2); 435-436. (Communication) |
Footnote
The flash photolysis spectrophotometer was comprised of an optical bench and optical components obtained from OLIS (Bogart Georgia) and a Phase-R DL1020 dye laser that was operated under computer control (Blue Moon Technical Services, Vancouver). The laser was operated with an ethanol solution of Coumarin 440 (Exciton, Inc.). Sample solutions were placed into a modified 10 mm cuvette and deaerated thoroughly with a vacuum line. Protein reduction was monitored at 550 nm, and kinetic data were analyzed with the program Scientist (version 2.0, MicroMath, Orem, UT). Electron transfer rate constants were independent of the concentration of the modified protein (50-150 μM). |
Konermann, L.,
Rosell, F. I.,
Mauk, A. G.,
Douglas, D. J. |
Acid-Induced Denaturation of Myoglobin Studied by Time-Resolved Electrospray Ionization Mass Spectrometry
Biochemistry; 1997; 36(21); 6448-6454. (Article) |
Experimental Procedures
Stopped-flow experiments were carried out with an Olis-RSM 1000 rapid scanning stopped-flow absorption spectrometer (Bogart, GA), the observation cell of which had a 1 cm path length. Conditions for hMb denaturation were identical to those of the time-resolved ESI MS experiments with the exception that the final protein concentration after mixing was 5 μM. The temperature of the solutions was held constant at 21 ˚C. |
Lloyd, E.,
Burk, D. L.,
Ferrer, J. C.,
Maurus, R.,
Doran, J.,
Carey, P. R.,
Brayer, G. D.,
Mauk, A. G. |
Electrostatic Modification of the Active Site of Myoglobin: Characterization of the Proximal Ser92Asp Variant
Biochemistry; 1996; 35(36); 11901-11912. (Article) |
Experimental Procedures
Determination of Distal Water pKa
The electronic spectrum of a sample of metMb in 0.10 M NaCl (pH ~6.0, 25.0C) was monitored as the pH of the solution was adjusted by incremental addition (<2 µL) of 0.10 M NaOH. Electronic spectra were recorded with a Cary 219 spectrophotometer interfaced to a microcomputer (OLIS, Bogart, GA) and fitted with a circulating thermostatted water bath. The pH of the sample was recorded before and after measurement of the spectrum. |
Rafferty, S. P.,
Guillemette, J. G.,
Berghuis, A. M.,
Smith, M., Brayer, G. D.,
Mauk, A. G. |
Mechanistic and Structural Contributions of Critical Surface and Internal Residues to Cytochrome c Electron Transfer Reactivity
Biochemistry; 1996; 35(33); 10784-10792. (Article) |
Experimental Procedures
Site-directed mutagenesis (Pielak et al., 1985; Inglis et al., 1991), protein expression and purification (Rafferty et al., 1990), and direct electrochemical measurements (Rafferty et al., 1990) of yeast iso-1-cytochrome c were performed as described previously. Kinetic experiments were performed with a Durrum Model D-110 stopped-flow spectrophotometer interfaced to a microcomputer (OLIS, Bogart, GA) and modified as described previously to improve anaerobicity (Reid & Mauk, 1982; Reid, 1984). The new variants constructed in this work were those involving internally located residues: Tyr67Phe, Asn52Ala, Thr78Gly, and Ile75Met. All variants also possessed the Cys102Thr substitution to eliminate complications arising from the reactive cysteine residue of the wild-type protein (Cutler et al., 1987). |
Koerner, R.,
Olmstead, M. M.,
Ozarowski, A.,
Phillips, S. L.,
Van Calcar, P. M.,
Winkler, K.,
Balch, A. L. |
Possible Intermediates in Biological Metalloporphyrin Oxidative Degradation. Nickel, Copper, and Cobalt Complexes of Octaethylformybiliverdin and Their Conversion to a Verdoheme
Journal of the American Chemical Society; 1998; 120(6); 1274-1284. (Article) |
Instrumentation
Absorption spectra were recorded on an OLIS/Cary-17 spectrophotometer or a Hewlet-Packard 8452A diode array spectrophotometer. |
Hays, A.-M. A.,
Vassiliev, I. R.,
Golbeck, J. H.,Debus, R. |
Role of D1-His190 in Proton-Coupled Electron Transfer Reactions in Photosystem II: A Chemical Complementation Study
Biochemistry; 1998; 37(32); 11352-11365. (Article) |
Materials and Methods
Optical Measurements in the UV and Visible Spectra
Transient absorbance changes of YZ at 242 nm (ΔA242), QA at 325 nm (ΔA325), and P680 at 432.5 nm (ΔA432.5) were measured with a modified CARY-14 spectrophotometer (On-Line Instrument Systems, Inc., Bogart, GA) operated in single-beam mode (chopper motor off) with the detector housing replaced by an end-on Hamamatsu R374 photomultiplier tube and a separate amplifier (EG&G Princeton Applied Research, model 5113). |
Arya, D. P.,
Bruice, T. C. |
Fidelity of Deoxynucleic S-Methythiourea (DNmt) Binding to DNA Oligomers: Influence of C Mismatches
Journal of the American Chemical Society; 1999 |
Experimental Section
CD, UV Spectroscopy, and Data Collection
CD spectra were obtained on an OLIS RSM circular dichroism spectrophotometer. Scans were run from 320 to 190 nm. Measurements were recorded at every nanometer. Ten scans were recorded, averaged, and smoothed for each curve. Samples were held in a 1 cm path length cuvette at 25 ˚C. |
Linkletter, B. A.,
Szabo, I. E.,
Bruice, T. C. |
Solid-Phase Synthesis of Deoxynucleic Guanidine (DNG) Oligomers and Melting Point and Circular Dichroism Analysis of Binding Fidelity of Octameric Thymidyl Oligomers with DNA Oligomers
Journal of the American Chemical Society; 1999; 121(16); 3888-3896. |
Experimental Section
Circular Dichroism Spectra
CD spectra were obtained on an OLIS RSM circular dichroism spectrophotometer. Scans were run from 350 to 210 nm taking a measurement every 1 nm. The integration time for each data point was 1.4 s. Ten scans were made of each sample and then averaged and smoothed using a 15 point exponential fitting algorithm. Samples were held in a 1 cm path-length cuvette and the temperature was maintained at 20 °C. |
