Abstract:
:Eleven amino acid positions in the helix-turn-helix of lambda repressor have been mutagenized by using a combinatorial method in which alanine is substituted at each position with a probability of 0.5. Approximately 25% of the 2048 proteins in the resulting binomial library are active, including some variants with as many as seven alanine substitutions. The frequency of alanine substitutions in the set of active variants is a measure of the importance of the wild-type residue at each mutagenized position, and comparison of the frequencies of pairwise mutations with those expected based upon the single-position frequencies allows the additivity of mutant effects to be tested. For the positions examined here, we find that the effects of multiple substitutions are largely additive and are able to predict the activity class of the binomial mutants with 90% accuracy by using a model that simply sums penalty scores derived from the alanine substitution frequencies. We also find, however, that several residue pairs, including some that are distant in the three-dimensional structure, do display nonadditive effects that appear to be statistically significant.
journal_name
Proc Natl Acad Sci U S Aauthors
Gregoret LM,Sauer RTdoi
10.1073/pnas.90.9.4246subject
Has Abstractpub_date
1993-05-01 00:00:00pages
4246-50issue
9eissn
0027-8424issn
1091-6490journal_volume
90pub_type
杂志文章abstract::Canavan's disease (CD) is a fatal, hereditary disorder of CNS development that has been linked to mutations in the gene for the enzyme aspartoacylase (ASPA) (EC 3.5.1.15). ASPA acts to hydrolyze N-acetylaspartate (NAA) into l-aspartate and acetate, but the connection between ASPA deficiency and the failure of proper C...
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.0409184102
更新日期:2005-04-05 00:00:00
abstract::As a master regulator of functional Ig heavy chain (IgH) expression, the IgH 3' regulatory region (3'RR) controls multiple transcription events at various stages of B-cell ontogeny, from newly formed B cells until the ultimate plasma cell stage. The IgH 3'RR plays a pivotal role in early B-cell receptor expression, ge...
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.1514090113
更新日期:2016-02-09 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.81.19.5999
更新日期:1984-10-01 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:2013-10-15 00:00:00
abstract::The human epidermal growth factor receptor 2 (HER2) is specifically overexpressed in tumors of several cancers, including an aggressive form of breast cancer. It is therefore a target for both cancer diagnostics and therapy. The 58 amino acid residue Zher2 affibody molecule was previously engineered as a high-affinity...
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pub_type: 杂志文章
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pub_type: 杂志文章
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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:1975-06-01 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:2015-10-06 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:1991-02-15 00:00:00
abstract::It was proved that the protoplasts prepared from mesophyll of Nicotiana tabacum are infected by tobacco mosaic virus. The infection occurred when purified tobacco mosaic virus particles were added to a protoplast suspension in the presence of poly-L-ornithine. The virus multiplied in these protoplasts to a level of 10...
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.93.13.6476
更新日期:1996-06-25 00:00:00
abstract::Based on the DNA sequence of the symbiotic plasmid of Rhizobium strain NGR234, we predicted potential rearrangements generated by homologous recombination. All predicted rearrangements were identified experimentally by using a PCR-based methodology. Thus, the predicted and the actual dynamic maps of the replicon coinc...
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.97.16.9138
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:2019-06-11 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.002024599
更新日期:2002-03-19 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
pub_type: 杂志文章
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更新日期:1991-07-01 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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更新日期:2001-07-17 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
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更新日期:2014-01-28 00:00:00
abstract::In most human follicular B cell lymphomas the bcl-2 gene is up-regulated as a result of the t(14;18) chromosomal translocation generating a hybrid bcl-2-IgH mRNA. Recently, we have identified in t(14;18)-positive cells a bcl-2-IgH mRNA in the antisense orientation, putatively responsible for the overexpression of bcl-...
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:1997-07-22 00:00:00
abstract::Although in decline after successful anti-HIV therapy, B-cell lymphomas are still elevated in HIV-1-seropositive (HIV+) persons, and the mechanisms are obscure. The HIV-1 matrix protein p17 persists in germinal centers long after HIV-1 drug suppression, and some p17 variants (vp17s) activate Akt signaling and promote ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 临床试验,杂志文章
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更新日期:2015-11-17 00:00:00
abstract::We have studied the properties of r-eag voltage-activated potassium channels in a stably transfected human embryonic kidney cell line. It was found that r-eag channels are rapidly and reversibly inhibited by a rise in intracellular calcium from 30 to 300 nM. The inhibition does not appear to depend on the activity of ...
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.93.18.9910
更新日期:1996-09-03 00:00:00
abstract::Amino-terminal sequence determinations are reported of the subunits of biliproteins of prokaryotic unicellular and filamentous cyanobacteria and of eukaryotic unicellular red algae. The biliproteins examined, allophycocyanin, C-phycocyanin, R-phycocyanin, b-phycoerythrin, and phycoerythrocyanin, vary with respect to t...
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.73.2.428
更新日期:1976-02-01 00:00:00
abstract::A mitochondrial gene from Saccharomyces cerevisiae encoding a hydrophobic membrane protein, subunit 8 of the F0/F1-type mitochondrial ATPase complex, has been functionally replaced by an artificial nuclear gene specifying an imported version of this protein. The experiments reported here utilized a multicopy expressio...
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.85.7.2091
更新日期:1988-04-01 00:00:00
abstract::There is an important medical need for new antifungal agents with novel mechanisms of action to treat the increasing number of patients with life-threatening systemic fungal disease and to overcome the growing problem of resistance to current therapies. F901318, the leading representative of a novel class of drug, the...
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.1608304113
更新日期:2016-11-08 00:00:00
abstract::Vanilloid receptor subunit 1 (VR1) appears to play a critical role in the transduction of noxious chemical and thermal stimuli by sensory nerve endings in peripheral tissues. Thus, VR1 antagonists are useful compounds to unravel the contribution of this receptor to pain perception, as well as to induce analgesia. We h...
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.022285899
更新日期:2002-02-19 00:00:00
abstract::Trypanosomatid RNA editing is a unique process and essential for these organisms. It therefore represents a drug target for a group of protozoa that includes the causative agents for African sleeping sickness and other devastating tropical and subtropical diseases. Here, we present drug-like inhibitors of a key enzyme...
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.0805820105
更新日期:2008-11-11 00:00:00
abstract::Albumin Redhill is an electrophoretically slow genetic variant of human serum albumin that does not bind 63Ni2+ and has a molecular mass 2.5 kDa higher than normal albumin. Its inability to bind Ni2+ was explained by the finding of an additional residue of Arg at position -1. This did not explain the molecular basis o...
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.87.1.26
更新日期:1990-01-01 00:00:00