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Updated: Jun 17, 2026
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Following Cell-fate in E. coli After Infection by Phage Lambda
Published on: October 14, 2011
Micron-scale holes terminate the phage infection cycle
Jill S Dewey1, Christos G Savva, Rebecca L White
1Department of Biochemistry and Biophysics, Microscopy and Imaging Center, Texas A&M University, College Station, TX 77843, USA.
Summary
Bacteriophage holins create unusually large membrane holes, over 340 nm wide, enabling rapid endolysin release and cell lysis. This discovery challenges existing models of holin function and viral infection dynamics.
Area of Science:
- Microbiology
- Structural Biology
- Virology
Background:
- Holins are essential phage proteins that induce bacterial cell lysis.
- During phage infection, holins accumulate in the cytoplasmic membrane and then form pores.
- These pores allow the release of endolysins, enzymes that degrade the cell wall, leading to lysis.
Purpose of the Study:
- To visualize and characterize the membrane lesions (holes) formed by the lambda-holin S105 in vivo.
- To determine the size, shape, and structural features of these holin-induced pores.
- To understand the implications of the pore size on the mechanism of phage-mediated cell lysis.
Main Methods:
- Cryo-electron microscopy (cryo-EM) was used to capture holin-induced holes in vivo.
- Cryo-electron tomography (cryo-ET) was employed for 3D structural analysis.
- Bacterial cell size was reduced by shifting to succinate minimal medium to facilitate cryo-tomographic imaging.
Main Results:
- Holin S105 formed exceptionally large membrane lesions, with an average diameter of 340 nm, some exceeding 1 micrometer.
- These holes were irregularly shaped and did not show evidence of membrane invagination.
- Coexpression of holin and endolysin resulted in spherical cells and collapsed inner membrane sacs due to cell wall degradation.
Conclusions:
- The unexpectedly large scale of holin-induced pores significantly impacts current models of holin function.
- These large lesions facilitate rapid and efficient release of endolysins, accelerating cell lysis.
- The findings provide new insights into the structural mechanisms of bacteriophage lysis.
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