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rdf:type |
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lifeskim:mentions |
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pubmed:issue |
5
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pubmed:dateCreated |
1993-6-24
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pubmed:abstractText |
Charge substitutions generated by site-directed mutagenesis at the termini of adjacent anti-parallel alpha-helices in a four-helix bundle protein were used to determine a precise value for the contribution of indirect charge-charge interactions to overall protein stability, and to simulate the electrostatic effects of alpha-helix macrodipoles. Thermodynamic double mutant cycles were constructed to measure the interaction energy between such charges on adjacent anti-parallel helices in the four-helix bundle cytochrome b562 from Escherichia coli. Previously, theoretical calculations of helix macrodipole interactions using modeled four-helix bundle proteins have predicted values ranging over an order of magnitude from 0.2 to 2.5 kcal/mol. Our system represents the first experimental evidence for electrostatic interactions such as those between partial charges due to helix macrodipole charges. At the positions mutated, we have measured a favorable interaction energy of 0.6 kcal/mol between opposite charges simulating an anti-parallel helix pair. Pairs of negative or positive charges simulating a parallel orientation of helices produce an unfavorable interaction of similar magnitude. The interaction energies show a strong dependence upon ionic strength, consistent with an electrostatic effect. Indirect electrostatic contacts do appear to confer a limited stabilization upon the association of anti-parallel packing of helices, favoring this orientation by as much as 1 kcal/mol at 20 mM K phosphate.
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pubmed:grant |
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pubmed:commentsCorrections |
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-1366956,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-1367432,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-1549776,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-1567817,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-1714279,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-1731929,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-1731930,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-1761034,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-1854726,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-1868051,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-1911766,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-1931945,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-1948029,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-2237415,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-2248951,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-2360048,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-2371258,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-2464850,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-2812029,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-2837825,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-2922396,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-3043666,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-3173493,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-3200317,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-3289117,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-3380793,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-3381086,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-3561498,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-368073,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-3689874,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-3885043,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-3892583,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-5330963,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-5432063,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-661956,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-6716485,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-6956878,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-7031264,
http://linkedlifedata.com/resource/pubmed/commentcorrection/8388289-7312043
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pubmed:language |
eng
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pubmed:journal |
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pubmed:citationSubset |
IM
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pubmed:chemical |
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pubmed:status |
MEDLINE
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pubmed:month |
May
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pubmed:issn |
0961-8368
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pubmed:author |
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pubmed:issnType |
Print
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pubmed:volume |
2
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
826-37
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pubmed:dateRevised |
2009-11-18
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pubmed:meshHeading |
pubmed-meshheading:8388289-Apoproteins,
pubmed-meshheading:8388289-Base Sequence,
pubmed-meshheading:8388289-Circular Dichroism,
pubmed-meshheading:8388289-Cytochrome c Group,
pubmed-meshheading:8388289-Escherichia coli,
pubmed-meshheading:8388289-Models, Chemical,
pubmed-meshheading:8388289-Models, Molecular,
pubmed-meshheading:8388289-Molecular Sequence Data,
pubmed-meshheading:8388289-Mutagenesis, Site-Directed,
pubmed-meshheading:8388289-Protein Conformation,
pubmed-meshheading:8388289-Protein Denaturation,
pubmed-meshheading:8388289-Protein Structure, Secondary,
pubmed-meshheading:8388289-Recombinant Proteins,
pubmed-meshheading:8388289-Thermodynamics
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pubmed:year |
1993
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pubmed:articleTitle |
Electrostatic stabilization in four-helix bundle proteins.
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pubmed:affiliation |
Department of Biochemistry, University of Illinois, Urbana 61801.
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pubmed:publicationType |
Journal Article,
Comparative Study,
Research Support, U.S. Gov't, P.H.S.
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