OXYGEN TRANSPORT: HEMOGLOBINS WITH MODIFIED HEMES
Principal Investigator: John Moffat
Abstract: To complete our present studies of modified hemes, we badly need crystals of heoglobin reconstituted with 2.4-dimethyl deuteroheme, and further attempts will be made. Almost the last readily accessible liganded hemoglobin is nitrite methemoglobin which is unusual as it may be either N- or O-bonded; X-ray studies may reveal this. As noted above, the question of heme orientation in native hemoglobin may have to be addressed via re-refinement of the heme, and we are contemplating this, perhaps in collaboration with Perutz. Kinetic studies on methemoglobin may also be conducted. The most interesting new project involves the use of the Cornell High Energy Synchrotron Source CHESS for EXAFS studies of our numerous crystallographically characterized hemoglobin derivatives, model prophyrins, and a series of cytochromes of varied redox potential. We have already obtained K- and L-edge spectra of lanthanides, and once a minor technical difficulty is overcome, see no problem in obtaining suitable K-edge spectra and Fe derivatives. The EXAFS data analysis package developed by Kincaid at Bell Labs has been readied and tested on our Prime computer, and beam time should not be in short supply, as I have been actively involved in this CHESS project from its inception.
Funding Period: 1978-05-01 - 1981-04-30
more information: NIH RePORT