Accurate crystallographic methods are being used to map the electron distribution of hemoglobin model compounds as a function of spin state, valency and coordination number. The research is to be focussed on small molecule (NO, CO, O2) adducts of porphyrins and cobalt Schiff bases to elucidate the electron nature of metal-adduct bonding which is essential for our understanding of the oxygen uptake mechanism. Specifically we will derive the amount of charge transfer from metal to ligand, the covalency of the metal ligand interaction and the asphericity of the metal atom charge distribution. This information is expected to fill important gaps in our present knowledge and answer a number of specific questions related to the extent to which changes in electronic structure of the heme contribute to the cooperativity mechanism for loading and unloading of oxygen. The results will aid in our understanding of the large number of biological processes involving heme proteins. Experimental data will be collected on conventional X-ray as well as synchrotron sources. In particular, the wiggler beamline at CHESS, the Cornell High Energy Synchrotron Source, will be used to obtain data at liquid helium temperature. The increased resolution available at low wavelenghts combined with very low temperatures constitute a major improvement in experimental methods.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL023884-08
Application #
3337441
Study Section
Biophysics and Biophysical Chemistry A Study Section (BBCA)
Project Start
1979-07-01
Project End
1989-11-30
Budget Start
1987-12-01
Budget End
1988-11-30
Support Year
8
Fiscal Year
1988
Total Cost
Indirect Cost
Name
State University of New York at Buffalo
Department
Type
Schools of Arts and Sciences
DUNS #
038633251
City
Buffalo
State
NY
Country
United States
Zip Code
14260
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Becker, P; Coppens, P (1990) About the Coulomb potential in crystals. Acta Crystallogr A 46 ( Pt 4):254-8
Mallinson, P R; Koritsanszky, T; Elkaim, E et al. (1988) The Gram-Charlier and multipole expansions in accurate X-ray diffraction studies: can they be distinguished? Acta Crystallogr A 44 ( Pt 3):336-42