NMR Study of the Molecular and Electronic Structure of the Heme Cavity of Aplysia Metmyoglobin. Resonance Assignments Based on Isotope Labeling and Proton Nuclear Overhauser Effect Measurements
The 1H NMR characteristics of the high-spin metmyoglobin from the mollusc Aplysia limacina have been investigated and compared with those of the myoglobin (Mb) from sperm whale. Aplysia metMb exhibits a normal acid ↔ alkaline transition with pK~ 7.8. In the acidic form, the heme methyl and meso prot...
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1986
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ftlouisianastuir:oai:digitalcommons.lsu.edu:chemistry_pubs-3009 2023-06-11T04:17:07+02:00 NMR Study of the Molecular and Electronic Structure of the Heme Cavity of Aplysia Metmyoglobin. Resonance Assignments Based on Isotope Labeling and Proton Nuclear Overhauser Effect Measurements Pande, Usha La Mar, Gerd N. Lecomte, Juliette T.J. Ascoli, Franca Brunori, Maurizio Smith, Kevin M. Pandey, Ravindra K. Parish, Daniel W. Thanabal, V. 1986-01-01T08:00:00Z https://digitalcommons.lsu.edu/chemistry_pubs/2008 https://doi.org/10.1021/bi00367a044 unknown LSU Digital Commons https://digitalcommons.lsu.edu/chemistry_pubs/2008 doi:10.1021/bi00367a044 Faculty Publications text 1986 ftlouisianastuir https://doi.org/10.1021/bi00367a044 2023-05-28T18:15:43Z The 1H NMR characteristics of the high-spin metmyoglobin from the mollusc Aplysia limacina have been investigated and compared with those of the myoglobin (Mb) from sperm whale. Aplysia metMb exhibits a normal acid ↔ alkaline transition with pK~ 7.8. In the acidic form, the heme methyl and meso proton resonances have been assigned by 1H NMR using samples reconstituted with selectively deuterated hemins and in the latter case by 2H NMR as well. On the basis of the methyl peak intensities and shift pattern, heme rotational disorder could be established in Aplysia Mb; ~20% of the protein exhibits a reversed heme orientation compared to that found in single crystals. Three meso proton resonances have been detected in the upfield region between -16 and -35 ppm, showing that the chemical shift of such protons can serve as a diagnostic probe for a pentacoordinated active site in hemoproteins, as previously shown to be the case in model compounds. The temperature dependence of the chemical shift of the meso proton signals deviates strongly from the T-1 Curie behavior, reflecting the presence of a thermally accessible Kramers doublet with significant S = 3/2 character. Nuclear Overhauser effect, NOE, measurements on Aplysia metMb have provided the assignment of individual heme a-propionate resonances and were used to infer spatial proximity among heme side chains. The hyperfine shift values for assigned resonances, the NOE connectivities, and the NOE magnitudes were combined to reach a qualitative picture of the rotational mobility and the orientation of the vinyl and propionate side chains of Aplysia metMb relative to sperm whale MbH20. Thus, it was found that the heme side chains are sterically less clamped in the former protein. © 1986, American Chemical Society. All rights reserved. Text Sperm whale LSU Digital Commons (Louisiana State University) Biochemistry 25 19 5638 5646 |
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LSU Digital Commons (Louisiana State University) |
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The 1H NMR characteristics of the high-spin metmyoglobin from the mollusc Aplysia limacina have been investigated and compared with those of the myoglobin (Mb) from sperm whale. Aplysia metMb exhibits a normal acid ↔ alkaline transition with pK~ 7.8. In the acidic form, the heme methyl and meso proton resonances have been assigned by 1H NMR using samples reconstituted with selectively deuterated hemins and in the latter case by 2H NMR as well. On the basis of the methyl peak intensities and shift pattern, heme rotational disorder could be established in Aplysia Mb; ~20% of the protein exhibits a reversed heme orientation compared to that found in single crystals. Three meso proton resonances have been detected in the upfield region between -16 and -35 ppm, showing that the chemical shift of such protons can serve as a diagnostic probe for a pentacoordinated active site in hemoproteins, as previously shown to be the case in model compounds. The temperature dependence of the chemical shift of the meso proton signals deviates strongly from the T-1 Curie behavior, reflecting the presence of a thermally accessible Kramers doublet with significant S = 3/2 character. Nuclear Overhauser effect, NOE, measurements on Aplysia metMb have provided the assignment of individual heme a-propionate resonances and were used to infer spatial proximity among heme side chains. The hyperfine shift values for assigned resonances, the NOE connectivities, and the NOE magnitudes were combined to reach a qualitative picture of the rotational mobility and the orientation of the vinyl and propionate side chains of Aplysia metMb relative to sperm whale MbH20. Thus, it was found that the heme side chains are sterically less clamped in the former protein. © 1986, American Chemical Society. All rights reserved. |
format |
Text |
author |
Pande, Usha La Mar, Gerd N. Lecomte, Juliette T.J. Ascoli, Franca Brunori, Maurizio Smith, Kevin M. Pandey, Ravindra K. Parish, Daniel W. Thanabal, V. |
spellingShingle |
Pande, Usha La Mar, Gerd N. Lecomte, Juliette T.J. Ascoli, Franca Brunori, Maurizio Smith, Kevin M. Pandey, Ravindra K. Parish, Daniel W. Thanabal, V. NMR Study of the Molecular and Electronic Structure of the Heme Cavity of Aplysia Metmyoglobin. Resonance Assignments Based on Isotope Labeling and Proton Nuclear Overhauser Effect Measurements |
author_facet |
Pande, Usha La Mar, Gerd N. Lecomte, Juliette T.J. Ascoli, Franca Brunori, Maurizio Smith, Kevin M. Pandey, Ravindra K. Parish, Daniel W. Thanabal, V. |
author_sort |
Pande, Usha |
title |
NMR Study of the Molecular and Electronic Structure of the Heme Cavity of Aplysia Metmyoglobin. Resonance Assignments Based on Isotope Labeling and Proton Nuclear Overhauser Effect Measurements |
title_short |
NMR Study of the Molecular and Electronic Structure of the Heme Cavity of Aplysia Metmyoglobin. Resonance Assignments Based on Isotope Labeling and Proton Nuclear Overhauser Effect Measurements |
title_full |
NMR Study of the Molecular and Electronic Structure of the Heme Cavity of Aplysia Metmyoglobin. Resonance Assignments Based on Isotope Labeling and Proton Nuclear Overhauser Effect Measurements |
title_fullStr |
NMR Study of the Molecular and Electronic Structure of the Heme Cavity of Aplysia Metmyoglobin. Resonance Assignments Based on Isotope Labeling and Proton Nuclear Overhauser Effect Measurements |
title_full_unstemmed |
NMR Study of the Molecular and Electronic Structure of the Heme Cavity of Aplysia Metmyoglobin. Resonance Assignments Based on Isotope Labeling and Proton Nuclear Overhauser Effect Measurements |
title_sort |
nmr study of the molecular and electronic structure of the heme cavity of aplysia metmyoglobin. resonance assignments based on isotope labeling and proton nuclear overhauser effect measurements |
publisher |
LSU Digital Commons |
publishDate |
1986 |
url |
https://digitalcommons.lsu.edu/chemistry_pubs/2008 https://doi.org/10.1021/bi00367a044 |
genre |
Sperm whale |
genre_facet |
Sperm whale |
op_source |
Faculty Publications |
op_relation |
https://digitalcommons.lsu.edu/chemistry_pubs/2008 doi:10.1021/bi00367a044 |
op_doi |
https://doi.org/10.1021/bi00367a044 |
container_title |
Biochemistry |
container_volume |
25 |
container_issue |
19 |
container_start_page |
5638 |
op_container_end_page |
5646 |
_version_ |
1768375949712162816 |