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B M Kincaid

Publications and source records attributed to B M Kincaid.

8 recordsLinked to original sources
PubMed1989

Comparison of the data, analysis, and results of X-ray absorption studies of cytochrome c oxidase.

Differences in the methods of analysis of X-ray absorption data used by Powers et al. [Powers, L., Blumberg, W. E., Chance, B., Barlow, C., Leigh, J., Jr., Smith, J., Yonetani, T., Vik, S., & Peisach, J. (1979) Biochim. Biophys. Acta 547, 520-538; Powers, L., Chance, B., Ching, Y., & Angiolillo, P. (1981) Biophys. J. 34, 465-498] and Scott et al. [Scott, R., Schwartz, J., & Cramer S. (1986) Biochemistry 25, 5546-5555] are clarified. In addition, we compare the X-ray absorption data and results for resting cytochrome c oxidase reported by both groups using the same analysis method and conclude apart from any assumptions that the data are not identical.

Copper↗
PubMed1982

NMR chemical shift imaging in three dimensions.

A method for obtaining the three-dimensional distribution of chemical shifts in a spatially inhomogeneous sample using Fourier transform NMR is presented. The method uses a sequence of pulsed field gradients to measure the Fourier transform of the desired distribution on a rectangular grid in (k,t) space. Simple Fourier inversion then recovers the original distribution. An estimated signal/noise ratio of 20 in 10 min is obtained for an "image" of the distribution of a 10 mM phosphorylated metabolite in the human head at a field of 20 kG with 2-cm resolution.

Fourier Analysis↗
PubMed1978

Extended X-ray absorption fine structure determination of iron nitrogen distances in haemoglobin.

EXAFS spectra have been obtained of oxy and deoxy complexes of haemoglobin and of the 'picket fence' porphyrin, using synchrotron radiation as a source of X rays. The fluorescence data were Fourier filtered to obtain distances to the first shell and corrections applied to remove contributions from the axial ligands. In this way, the iron to porphinato nitrogen distances were determined to be 1.98 +/- 0.01 A for both oxygenated complexes and 2.055 +/- 0.01 A for both deoxy forms.

Hemoglobins↗
PubMed1978

EXAFS: new horizons in structure determinations.

Although the phenomena of extended x=ray absorption fine structure (EXAFS) were observed as early as the 1930's, EXAFS has only recently, with the utilization of synchrotron radiation, been transformed into a powerful structural technique. The theory and experimental practice of the technique are described and illustrated with data on germanium. Applications to systems as diverse as hemoglobin, polymer-bound catalysts, ions in solution, amorphous solids, and adsorbate atoms on surfaces are reviewed. With the recent approval of funding for new, more powerful dedicated synchrotron sources, the future holds the possibility of a virtual revolution in structure determinations.

Chemical Phenomena↗
PubMed1975

X-ray absorption spectroscopy using synchrotron radiation for structural investigation of organometallic molecules of biological interest.

The technique of x-ray absorption spectroscopy using tuneable, very intense x-rays from a high energy electron storage ring has been applied to study of the estended x-ray absorption fine structure for Cu and Ni tetraphenylporphyrin and methemoglobin. Preliminary analysis shows that the spectra may be interpreted as a super-position of modulations arising from the nearest neighbor nitrogen and pyrrole alpha-carbon coordination sheels of the metal atoms. We estimate that with the observed magnitude of noise to modulation amplitude, relative shifts of 0,5% in the metal-nitrogen to metal-carbon bond distances in the prophyrins should be observable using extended x-ray absorption fine structure and that this technique may provide a method of observing these types of structural changes in solution.

Copper↗