Abstract:
:We estimated the unliganded opening and closing rate constants of neuromuscular acetylcholine receptor-channels (AChRs) having mutations that increased the gating equilibrium constant. For some mutant combinations, spontaneous openings occurred in clusters. For 25 different constructs, the unliganded gating equilibrium constant (E(0)) was correlated with the product of the predicted fold-increase in the diliganded gating equilibrium constant caused by each mutation alone. We estimate that (i) E(0) for mouse, wild-type alpha(2)beta delta epsilon AChRs is approximately 1.15 x 10(-7); (ii) unliganded AChRs open for approximately 80 micros, once every approximately 15 min; (iii) the affinity for ACh of the O(pen) conformation is approximately 10 nM, or approximately 15,600 times greater than for the C(losed) conformation; (iv) the ACh-monoliganded gating equilibrium constant is approximately 1.7 x 10(-3); (v) the C-->O isomerization reduces substantially ACh dissociation, but only slightly increases association; and (vi) ACh provides only approximately 0.9 k(B)T more binding energy per site than carbamylcholine but approximately 3.1 k(B)T more than choline, mainly because of a low O conformation affinity. Most mutations of binding site residue alphaW149 increase E(0). We estimate that the mutation alphaW149F reduces the ACh affinity of C only by 13-fold, but of O by 190-fold. Rate-equilibrium free-energy relationships for different regions of the protein show similar slopes (Phi values) for un- vs. diliganded gating, which suggests that the conformational pathway of the gating structural change is fundamentally the same with and without agonists. Agonist binding is a perturbation that (like most mutations) changes the energy, but not the mechanism, of the gating conformational change.
journal_name
Proc Natl Acad Sci U S Aauthors
Purohit P,Auerbach Adoi
10.1073/pnas.0809272106subject
Has Abstractpub_date
2009-01-06 00:00:00pages
115-20issue
1eissn
0027-8424issn
1091-6490pii
0809272106journal_volume
106pub_type
杂志文章abstract::Treatment of a human breast cancer cell line (MDA-MB-435) in nude mice with a recombinant adenovirus containing the human interferon (IFN) consensus gene, IFN-con1 (ad5/IFN), resulted in tumor regression in 100% of the animals. Tumor regression occurred when virus was injected either within 24 hr of tumor cell implant...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.93.9.4513
更新日期:1996-04-30 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0602856103
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.90.6.2315
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pub_type: 杂志文章
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更新日期:2019-09-17 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.73.1.152
更新日期:1976-01-01 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2007-05-08 00:00:00
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pub_type: 临床试验,杂志文章
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更新日期:2009-03-10 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.64.3.843
更新日期:1969-11-01 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1316521110
更新日期:2013-12-10 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.93.15.7649
更新日期:1996-07-23 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.68.10.2477
更新日期:1971-10-01 00:00:00
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更新日期:1996-01-09 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.90.8.3544
更新日期:1993-04-15 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:1988-07-01 00:00:00
abstract::We have previously observed the spontaneous, pH-dependent insertion of a water-soluble peptide to form a helix across lipid bilayers [Hunt, J. F., Rath, P., Rothschild, K. J. & Engelman, D. M. (1997) Biochemistry 36, 15177-15192]. We now use a related peptide, pH (low) insertion peptide, to translocate cargo molecules...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
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更新日期:2006-04-25 00:00:00
abstract::cis-jasmone, or (Z)-jasmone, is well known as a component of plant volatiles, and its release can be induced by damage, for example during insect herbivory. Using the olfactory system of the lettuce aphid to investigate volatiles from plants avoided by this insect, (Z)-jasmone was found to be electrophysiologically ac...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2000-08-01 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:1996-11-12 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1337088100
更新日期:2003-06-24 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2000-08-15 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.73.7.2458
更新日期:1976-07-01 00:00:00
abstract::The eukaryotic microorganism Saccharomyces cerevisiae contains 50-100 copies per cell of a circular plasmid called 2-micrometer DNA. The intracellular structure of these molecules, which represent about 4% of the total DNA, was examined by digestion of total cellular chromatin with micrococcal nuclease (nucleate 3'-ol...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:1979-12-01 00:00:00