Putative interhelix ion pairs involved in the stability of myoglobin
ABSTRACT: An earlier theoretical study predicted that specific ion pair interactions between neighboring helices should be important in stabilizing myoglobin. To measure these interactions in sperm whale myoglobin, single mutations were made to disrupt them. To obtain reliable ¢G values, conditions...
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ftciteseerx:oai:CiteSeerX.psu:10.1.1.664.4711 2023-05-15T18:26:48+02:00 Putative interhelix ion pairs involved in the stability of myoglobin Carlos H. I. Ramos Michael S. Kay Robert L. Baldwin The Pennsylvania State University CiteSeerX Archives 1999 application/pdf http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.664.4711 http://rbaldwin.stanford.edu/PDFs/putative_interhelix_ion_pairs.pdf en eng http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.664.4711 http://rbaldwin.stanford.edu/PDFs/putative_interhelix_ion_pairs.pdf Metadata may be used without restrictions as long as the oai identifier remains attached to it. http://rbaldwin.stanford.edu/PDFs/putative_interhelix_ion_pairs.pdf text 1999 ftciteseerx 2016-01-08T17:01:53Z ABSTRACT: An earlier theoretical study predicted that specific ion pair interactions between neighboring helices should be important in stabilizing myoglobin. To measure these interactions in sperm whale myoglobin, single mutations were made to disrupt them. To obtain reliable ¢G values, conditions were found in which the urea induced unfolding of holomyoglobin is reversible and two-state. The cyanomet form of myoglobin satisfies this condition at pH 5, 25 °C. The unfolding curves monitored by far-UV CD and Soret absorbance are superimposable and reversible. None of the putative ion pairs studied here makes a large contribution to the stability of native myoglobin. The protein stability does decrease somewhat between 0 and 0.1 M NaCl, however, indicating that electrostatic interactions contribute favorably to myoglobin stability at pH 5.0. A previous mutational study indicated that the net positive charge of the A[B]GH subdomain of myoglobin is an important factor affecting the stability of the pH 4 folding intermediate and potential ion pairs within the subdomain do not contribute significantly to its stability. One of the assumptions made in that study is tested here: replacement of either positively or negatively charged residues outside the A[B]GH subdomain has no significant effect on the stability of the pH 4 molten globule. Pairs of oppositely charged residues on adjacent helices Text Sperm whale Unknown |
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description |
ABSTRACT: An earlier theoretical study predicted that specific ion pair interactions between neighboring helices should be important in stabilizing myoglobin. To measure these interactions in sperm whale myoglobin, single mutations were made to disrupt them. To obtain reliable ¢G values, conditions were found in which the urea induced unfolding of holomyoglobin is reversible and two-state. The cyanomet form of myoglobin satisfies this condition at pH 5, 25 °C. The unfolding curves monitored by far-UV CD and Soret absorbance are superimposable and reversible. None of the putative ion pairs studied here makes a large contribution to the stability of native myoglobin. The protein stability does decrease somewhat between 0 and 0.1 M NaCl, however, indicating that electrostatic interactions contribute favorably to myoglobin stability at pH 5.0. A previous mutational study indicated that the net positive charge of the A[B]GH subdomain of myoglobin is an important factor affecting the stability of the pH 4 folding intermediate and potential ion pairs within the subdomain do not contribute significantly to its stability. One of the assumptions made in that study is tested here: replacement of either positively or negatively charged residues outside the A[B]GH subdomain has no significant effect on the stability of the pH 4 molten globule. Pairs of oppositely charged residues on adjacent helices |
author2 |
The Pennsylvania State University CiteSeerX Archives |
format |
Text |
author |
Carlos H. I. Ramos Michael S. Kay Robert L. Baldwin |
spellingShingle |
Carlos H. I. Ramos Michael S. Kay Robert L. Baldwin Putative interhelix ion pairs involved in the stability of myoglobin |
author_facet |
Carlos H. I. Ramos Michael S. Kay Robert L. Baldwin |
author_sort |
Carlos H. I. Ramos |
title |
Putative interhelix ion pairs involved in the stability of myoglobin |
title_short |
Putative interhelix ion pairs involved in the stability of myoglobin |
title_full |
Putative interhelix ion pairs involved in the stability of myoglobin |
title_fullStr |
Putative interhelix ion pairs involved in the stability of myoglobin |
title_full_unstemmed |
Putative interhelix ion pairs involved in the stability of myoglobin |
title_sort |
putative interhelix ion pairs involved in the stability of myoglobin |
publishDate |
1999 |
url |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.664.4711 http://rbaldwin.stanford.edu/PDFs/putative_interhelix_ion_pairs.pdf |
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Sperm whale |
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Sperm whale |
op_source |
http://rbaldwin.stanford.edu/PDFs/putative_interhelix_ion_pairs.pdf |
op_relation |
http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.664.4711 http://rbaldwin.stanford.edu/PDFs/putative_interhelix_ion_pairs.pdf |
op_rights |
Metadata may be used without restrictions as long as the oai identifier remains attached to it. |
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1766208762003062784 |