Abstract:
:The configuration of the heme-carbonyl group upon binding of carbon monoxide to sperm whale myoglobin (Mb) in crystals is evaluated on the basis of infrared spectroscopic methods. Multiplets of the totally symmetric C-O stretching mode are observed for the heme-bound ligand near 1933, 1944, and 1967 cm-1, corresponding to three different heme-carbonyl conformers. Variations in the relative proportions of these conformers can be induced by incorporation of small fractions of metMb or deoxyMb into MbCO crystals. The configuration of the iron-carbonyl with respect to the immediate coordination environment of the heme iron is assigned for each v(CO) stretching frequency on the basis of a detailed comparison of the three-dimensional structures of the heme environments of MbCO, metMb, and deoxyMb defined by crystallographic methods. The structures of the three heme-carbonyl conformers account for the v(CO) infrared absorption bands that can be observed for MbCO in solution.
journal_name
Proc Natl Acad Sci U S Aauthors
Makinen MW,Houtchens RA,Caughey WSdoi
10.1073/pnas.76.12.6042subject
Has Abstractpub_date
1979-12-01 00:00:00pages
6042-6issue
12eissn
0027-8424issn
1091-6490journal_volume
76pub_type
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