Portal Stability Controls Dynamics of DNA Ejection from Phage
Freeman, Krista G. ; Behrens, Manja A. LU ; Streletzky, Kiril A. ; Olsson, Ulf LU and Evilevitch, Alex LU
(2016)
In Journal of Physical Chemistry B
120(26).
p.6421-6429
- Abstract
Through a unique combination of time-resolved single-molecule (cryo-TEM) and bulk measurements (light scattering and small-angle X-ray scattering), we provide a detailed study of the dynamics of stochastic DNA ejection events from phage λ. We reveal that both binding with the specific phage receptor, LamB, and thermo-mechanical destabilization of the portal vertex on the capsid are required for initiation of ejection of the pressurized λ-DNA from the phage. Specifically, we found that a measurable activation energy barrier for initiation of DNA ejection with LamB present, Ea = (1.2 ± 0.1) × 10-19 J/phage (corresponding to ∼28 kTbody/phage at Tbody = 37 °C), results in 15 times increased rate... (More)
Through a unique combination of time-resolved single-molecule (cryo-TEM) and bulk measurements (light scattering and small-angle X-ray scattering), we provide a detailed study of the dynamics of stochastic DNA ejection events from phage λ. We reveal that both binding with the specific phage receptor, LamB, and thermo-mechanical destabilization of the portal vertex on the capsid are required for initiation of ejection of the pressurized λ-DNA from the phage. Specifically, we found that a measurable activation energy barrier for initiation of DNA ejection with LamB present, Ea = (1.2 ± 0.1) × 10-19 J/phage (corresponding to ∼28 kTbody/phage at Tbody = 37 °C), results in 15 times increased rate of ejection event dynamics when the temperature is raised from 15 to 45 °C (7.5 min versus 30 s average lag time for initiation of ejection). This suggests that phages have a double fail-safe mechanism for ejection - in addition to receptor binding, phage must also overcome (through thermal energy and internal DNA pressure) an energy barrier for DNA ejection. This energy barrier ensures that viral genome ejection into cells occurs with high efficiency only when the temperature conditions are favorable for genome replication. At lower suboptimal temperatures, the infectious phage titer is preserved over much longer times, since DNA ejection dynamics is strongly inhibited even in the presence of solubilized receptor or susceptible cells. This work also establishes a light scattering based approach to investigate the influence of external solution conditions, mimicking those of the bacterial cytoplasm, on the stability of the viral capsid portal, which is directly linked to dynamics of virion deactivation.
(Less)
- author
- Freeman, Krista G.
; Behrens, Manja A.
LU
; Streletzky, Kiril A.
; Olsson, Ulf
LU
and Evilevitch, Alex
LU
- organization
- publishing date
- 2016-07-07
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Journal of Physical Chemistry B
- volume
- 120
- issue
- 26
- pages
- 9 pages
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- scopus:84978076667
- pmid:27176921
- wos:000379457200071
- ISSN
- 1520-6106
- DOI
- 10.1021/acs.jpcb.6b04172
- language
- English
- LU publication?
- yes
- id
- 851b2cce-802f-4cee-ba87-a41dd03eb066
- date added to LUP
- 2017-01-12 14:20:11
- date last changed
- 2024-04-05 12:58:05
@article{851b2cce-802f-4cee-ba87-a41dd03eb066,
abstract = {{<p>Through a unique combination of time-resolved single-molecule (cryo-TEM) and bulk measurements (light scattering and small-angle X-ray scattering), we provide a detailed study of the dynamics of stochastic DNA ejection events from phage λ. We reveal that both binding with the specific phage receptor, LamB, and thermo-mechanical destabilization of the portal vertex on the capsid are required for initiation of ejection of the pressurized λ-DNA from the phage. Specifically, we found that a measurable activation energy barrier for initiation of DNA ejection with LamB present, E<sub>a</sub> = (1.2 ± 0.1) × 10<sup>-19</sup> J/phage (corresponding to ∼28 kT<sub>body</sub>/phage at T<sub>body</sub> = 37 °C), results in 15 times increased rate of ejection event dynamics when the temperature is raised from 15 to 45 °C (7.5 min versus 30 s average lag time for initiation of ejection). This suggests that phages have a double fail-safe mechanism for ejection - in addition to receptor binding, phage must also overcome (through thermal energy and internal DNA pressure) an energy barrier for DNA ejection. This energy barrier ensures that viral genome ejection into cells occurs with high efficiency only when the temperature conditions are favorable for genome replication. At lower suboptimal temperatures, the infectious phage titer is preserved over much longer times, since DNA ejection dynamics is strongly inhibited even in the presence of solubilized receptor or susceptible cells. This work also establishes a light scattering based approach to investigate the influence of external solution conditions, mimicking those of the bacterial cytoplasm, on the stability of the viral capsid portal, which is directly linked to dynamics of virion deactivation.</p>}},
author = {{Freeman, Krista G. and Behrens, Manja A. and Streletzky, Kiril A. and Olsson, Ulf and Evilevitch, Alex}},
issn = {{1520-6106}},
language = {{eng}},
month = {{07}},
number = {{26}},
pages = {{6421--6429}},
publisher = {{The American Chemical Society (ACS)}},
series = {{Journal of Physical Chemistry B}},
title = {{Portal Stability Controls Dynamics of DNA Ejection from Phage}},
url = {{http://dx.doi.org/10.1021/acs.jpcb.6b04172}},
doi = {{10.1021/acs.jpcb.6b04172}},
volume = {{120}},
year = {{2016}},
}