| Micron-scale holes terminate the phage infection cycle. | |
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MedLine Citation:
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PMID: 20080651 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Holins are small phage-encoded proteins that accumulate harmlessly in the cytoplasmic membrane during the infection cycle until suddenly, at an allele-specific time, triggering to form lethal lesions, or "holes." In the phages lambda and T4, the holes have been shown to be large enough to allow release of prefolded active endolysin from the cytoplasm, which results in destruction of the cell wall, followed by lysis within seconds. Here, the holes caused by S105, the lambda-holin, have been captured in vivo by cryo-EM. Surprisingly, the scale of the holes is at least an order of magnitude greater than any previously described membrane channel, with an average diameter of 340 nm and some exceeding 1 microm. Most cells exhibit only one hole, randomly positioned in the membrane, irrespective of its size. Moreover, on coexpression of holin and endolysin, the degradation of the cell wall leads to spherically shaped cells and a collapsed inner membrane sac. To obtain a 3D view of the hole by cryo-electron tomography, we needed to reduce the average size of the cells significantly. By taking advantage of the coupling of bacterial cell size and growth rate, we achieved an 80% reduction in cell mass by shifting to succinate minimal medium for inductions of the S105 gene. Cryotomographic analysis of the holes revealed that they were irregular in shape and showed no evidence of membrane invagination. The unexpected scale of these holes has implications for models of holin function. |
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Authors:
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Jill S Dewey; Christos G Savva; Rebecca L White; Stanislav Vitha; Andreas Holzenburg; Ry Young |
Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't Date: 2010-01-11 |
Journal Detail:
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Title: Proceedings of the National Academy of Sciences of the United States of America Volume: 107 ISSN: 1091-6490 ISO Abbreviation: Proc. Natl. Acad. Sci. U.S.A. Publication Date: 2010 Feb |
Date Detail:
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Created Date: 2010-02-05 Completed Date: 2010-03-05 Revised Date: 2010-09-27 |
Medline Journal Info:
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Nlm Unique ID: 7505876 Medline TA: Proc Natl Acad Sci U S A Country: United States |
Other Details:
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Languages: eng Pagination: 2219-23 Citation Subset: IM |
Affiliation:
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Department of Biochemistry and Biophysics, Microscopy and Imaging Center, Texas A&M University, College Station, TX 77843, USA. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Bacteriophage lambda
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genetics,
pathogenicity*,
physiology Cryoelectron Microscopy Endopeptidases / genetics, physiology Escherichia coli / ultrastructure, virology* Genes, Viral Viral Proteins / genetics, physiology |
| Grant Support | |
ID/Acronym/Agency:
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GM27099/GM/NIGMS NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Viral Proteins; 0/bacteriophage lambda lysis effector protein S105; 150201-54-0/Rz protein, bacteriophage lambda; EC 3.4.-/Endopeptidases; EC 3.4.99.-/endolysin |
| Comments/Corrections | |
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