Source:http://linkedlifedata.com/resource/pubmed/id/20156449
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
4
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pubmed:dateCreated |
2010-3-26
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pubmed:abstractText |
AlfA is a recently discovered DNA segregation protein from Bacillus subtilis that is distantly related to actin and the bacterial actin homologues ParM and MreB. Here we show that AlfA mostly forms helical 7/3 filaments, with a repeat of about 180 A, that are arranged in three-dimensional bundles. Other polymorphic structures in the form of two-dimensional rafts or paracrystalline nets were also observed. Here AlfA adopted a 16/7 helical symmetry, with a repeat of about 387 A. Thin polymers consisting of several intertwining filaments also formed. Observed helical symmetries of AlfA filaments differed from those of other members of the actin family: F-actin, ParM, or MreB. Both ATP and guanosine 5'-triphosphate are able to promote rapid AlfA filament formation with almost equal efficiencies. The helical structure is only preserved under physiological salt concentrations and at a pH between 6.4 and 7.4, the physiological range of the cytoplasm of B. subtilis. Polymerization kinetics are extremely rapid and compatible with a cooperative assembly mechanism requiring only two steps: monomer activation followed by elongation, making AlfA one of the most efficient polymerizing motors within the actin family. Phosphate release lags behind polymerization, and time-lapse total internal reflection fluorescence images of AlfA bundles are consistent with treadmilling rather than dynamic microtubule-like instability. High-pressure small angle X-ray scattering experiments reveal that the stability of AlfA filaments is intermediate between the stability of ParM and the stability of F-actin. These results emphasize that actin-like polymerizing machineries have diverged to produce a variety of filament geometries with diverse properties that are tailored for specific biological processes.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Actins,
http://linkedlifedata.com/resource/pubmed/chemical/Adenosine Triphosphate,
http://linkedlifedata.com/resource/pubmed/chemical/Bacterial Proteins,
http://linkedlifedata.com/resource/pubmed/chemical/Guanosine Triphosphate,
http://linkedlifedata.com/resource/pubmed/chemical/Sodium Chloride
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pubmed:status |
MEDLINE
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pubmed:month |
Apr
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pubmed:issn |
1089-8638
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pubmed:author | |
pubmed:copyrightInfo |
(c) 2010 Elsevier Ltd. All rights reserved.
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pubmed:issnType |
Electronic
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pubmed:day |
9
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pubmed:volume |
397
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
1031-41
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pubmed:dateRevised |
2011-11-17
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pubmed:meshHeading |
pubmed-meshheading:20156449-Actin Cytoskeleton,
pubmed-meshheading:20156449-Actins,
pubmed-meshheading:20156449-Adenosine Triphosphate,
pubmed-meshheading:20156449-Bacillus subtilis,
pubmed-meshheading:20156449-Bacterial Proteins,
pubmed-meshheading:20156449-Fourier Analysis,
pubmed-meshheading:20156449-Guanosine Triphosphate,
pubmed-meshheading:20156449-Hydrogen-Ion Concentration,
pubmed-meshheading:20156449-Microscopy, Electron, Transmission,
pubmed-meshheading:20156449-Models, Molecular,
pubmed-meshheading:20156449-Protein Multimerization,
pubmed-meshheading:20156449-Protein Stability,
pubmed-meshheading:20156449-Scattering, Small Angle,
pubmed-meshheading:20156449-Sodium Chloride
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pubmed:year |
2010
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pubmed:articleTitle |
Polymeric structures and dynamic properties of the bacterial actin AlfA.
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pubmed:affiliation |
ERATO Actin Filament Dynamics Project, Japan Science and Technology Corporation, c/o RIKEN Harima Institute at Spring 8, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan. dpopp@imcb.a-star.edu.sg
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pubmed:publicationType |
Journal Article,
Research Support, Non-U.S. Gov't
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