Nuclear magnetic resonance studies of carbon-13 monoxide binding to various hemoglobins

Moon, Richard B.; Richards, John H.

doi:10.1021/ja00769a058

Cited by 44 publications

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“…Both l3C magnetic resonance (Moon & Richards, 1972; Matwiyoff et al, 1973;) and infrared techniques (Alben & Caughey, 1968;Caughey et al, 1969;Maxwell et al, 1974) have been applied. The work of this paper concentrates on infrared studies of these interactions in which both the frequencies and intensities of the various absorptions have been determined for human, horse, and rabbit hemoglobins.…”

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Spectroscopic studies of the nature of ligand bonding in carbonmonoxyhemoglobins: evidence of a specific function for histidine-E7 from infrared and nuclear magnetic resonance intensities

Satterlee¹,

Teintze²,

Richards³

1978

Biochemistry

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Infrared spectra of carbon monoxide ligated hemoglobins from human, horse, and rabbit donors have been examined. A single vibrational frequency at 1951 cm-1 is observed for CO bound to the heme in horse and human hemoglobins. Studies of the isolated alpha-CO and beta-CO subunits of human hemoglobin reveal that the observation of a single frequency in the intact tetramer is the result of a superposition of the alpha-CO and beta-CO vibrational frequencies. The apparent integrated absorption intensities of these CO vibrations are shown both to have values of 1.0 X 10(5)M-1cm-2 within experimental error. For rabbit CO-Hb two vibrational frequencies appear (Caughey, W. S., et al. (1973) Fed. Proc., Fed. Am. Soc. Exp. Biol. 32, 552) and are assigned to CO bound to the beta (1951 cm-1) and alpha(1928 cm-1) subunits within the intact tetramer. The beta-CO subunit exhibits both frequency and intensity similarities with horse and human hemoglobins. The rabbit alpha-CO subunit, however, exhibits a markedly lower frequency and much smaller intensity compared with the other CO-hemoglobins. These data are interpreted in terms of a specific role for the distal histidine (E7) in rabbit alpha subunits, in which this histidine functions as a nucleophilic donor to coordinated CO.

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Spectroscopic studies of the nature of ligand bonding in carbonmonoxyhemoglobins: evidence of a specific function for histidine-E7 from infrared and nuclear magnetic resonance intensities

Satterlee¹,

Teintze²,

Richards³

1978

Biochemistry

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“…The asymmetry of the shielding tensor of all the heme model compounds studied is significantly smaller than that found for horse myoglobin and rabbit hemoglobin (see Table ). , For Mb 13 CO the increase in asymmetry may be attributed to an interaction in the A 3 substrate, which was found to be the major conformer in the samples used for 13 C CP MAS NMR measurements,22a of the N ε lone pair of the distal histidine with the CO π* orbital. , Such a hypothesis is supported from neutron diffraction structure analysis which showed that there was no hydrogen bond between CO and the distal histidine residue and that the N ε atom is not deuterated. Apparently the imidazole proton resides on N δ .…”

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confidence: 79%

¹³C CP/MAS NMR Studies of Hemoprotein Models with and without an Axial Hindered Base: ¹³C Shielding Tensors and Comparison with Hemoproteins and X-ray Structural Data

et al. 1996

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13C cross-polarization magic-angle-spinning (CP/MAS) NMR spectra of several carbonmonoxide (93-99% (13)C enriched) hemoprotein models with 1,2-dimethylimidazole (1,2-diMeIm) and 1-methylimidazole (1-MeIm) as axial ligands are reported. This enables the (13)CO spinning sideband manifold to be measured and hence the principal components of the (13)CO chemical shift tensor to be obtained. Negative polar interactions in the binding pocket of the cap porphyrin model and inhibition of Fe-->CO back-donation result in a reduction in shielding anisotropy; on the contrary, positive distal polar interactions result in an increase in the shielding anisotropy and asymmetry parameter in some models. It appears that the axial hindered base 1,2-dimethylimidazole has little direct effect on the local geometry at the CO site, despite higher rates of CO desorption being observed for such complexes. This suggests that the mechanism by which steric interactions are released for the 1,2-diMeIm complexes compared to 1-MeIm complexes does not involve a significant increase in bending of the Fe-C-O unit. The asymmetry of the shielding tensor of all the heme model compounds studied is smaller than that found for horse myoglobin and rabbit hemoglobin.

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“…Kinetic differences in the affinities of the a and ß subunits in binding ligands such as nitric oxide, «-butyl isocyanide, and oxygen have been reported (Henry & Cassoly, 1973; Olson & Gibson, 1972;Gibson, 1973). Environmental differences experienced by CO bound to « or ß subunits have been observed (Moon & Richards, 1972bMatwlyoff & Needham, 1972;Matwlyoff et al, 1973;Vergamini et al, 1973). Differences in protein conformation surrounding the heme in the a and ß subunits of carboxyhemoglobins have been established by 1H NMR techniques.…”

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confidence: 99%

¹³C nuclear magnetic resonance studies of the binding of isocyanides to various hemoglobins and myoglobins

Dill¹,

Satterlee²,

Richards³

1978

Biochemistry

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Interactions between ethyl and isopropyl isocyanides and various hemoglobins and myoglobins have been studied by 13C nuclear magnetic resonance. The results indicate that the chemical shift of the bound isocyanide depends on the structure of the hemoglobin subunit or myoglobin. The resonances exhibited by isocyanides bound to myoglobin are sensitive to pH in contrast to the situation with rabbit and human hemoglobins. beta subunits of opossum, rabbit, and human hemoglobins show a significantly greater preferential affinity for CO relative to EIC than do alpha subunits which have allowed the assignment of resonances. Rabbit, human, and opossum hemoglobin subunits bind ethyl isocyanide without observable preferences and an excess of DPG does not appear to affect this random order of ligation. In contrast, an excess of IHP seems to cause preferential ligation of the alpha subunits in these hemoglobins. The results have been used to gain insights into the differing characteristics of the ligand binding pockets of these various hemoglobins.

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Nuclear magnetic resonance studies of carbon-13 monoxide binding to various hemoglobins

Cited by 44 publications

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Spectroscopic studies of the nature of ligand bonding in carbonmonoxyhemoglobins: evidence of a specific function for histidine-E7 from infrared and nuclear magnetic resonance intensities

Spectroscopic studies of the nature of ligand bonding in carbonmonoxyhemoglobins: evidence of a specific function for histidine-E7 from infrared and nuclear magnetic resonance intensities

¹³C CP/MAS NMR Studies of Hemoprotein Models with and without an Axial Hindered Base: ¹³C Shielding Tensors and Comparison with Hemoproteins and X-ray Structural Data

¹³C nuclear magnetic resonance studies of the binding of isocyanides to various hemoglobins and myoglobins

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Nuclear magnetic resonance studies of carbon-13 monoxide binding to various hemoglobins

Cited by 44 publications

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Spectroscopic studies of the nature of ligand bonding in carbonmonoxyhemoglobins: evidence of a specific function for histidine-E7 from infrared and nuclear magnetic resonance intensities

Spectroscopic studies of the nature of ligand bonding in carbonmonoxyhemoglobins: evidence of a specific function for histidine-E7 from infrared and nuclear magnetic resonance intensities

13C CP/MAS NMR Studies of Hemoprotein Models with and without an Axial Hindered Base: 13C Shielding Tensors and Comparison with Hemoproteins and X-ray Structural Data

13C nuclear magnetic resonance studies of the binding of isocyanides to various hemoglobins and myoglobins

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¹³C CP/MAS NMR Studies of Hemoprotein Models with and without an Axial Hindered Base: ¹³C Shielding Tensors and Comparison with Hemoproteins and X-ray Structural Data

¹³C nuclear magnetic resonance studies of the binding of isocyanides to various hemoglobins and myoglobins