skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Binding-induced Stabilization and Assembly of the Phage P22 Tail Accessory Factor gp4

Abstract

To infect and replicate, bacteriophage P22 injects its 43 kbp genome across the cell wall of Salmonella enterica serovar Typhimurium. The attachment of phage P22 to the host cell as well as the injection of the viral DNA into the host is mediated by the virion's tail complex. This 2.8 MDa molecular machine is formed by five proteins, which include the portal protein gp1, the adhesion tailspike protein gp9, and three tail accessory factors: gp4, gp10, gp26. We have isolated the tail accessory factor gp4 and characterized its structure and binding interactions with portal protein. Interestingly, gp4 exists in solution as a monomer, which displays an exceedingly low structural stability (T{sub m} 34 {sup o}C). Unfolded gp4 is prone to aggregation within a narrow range of temperatures both in vitro and in Salmonella extracts. In the virion the thermal unfolding of gp4 is prevented by the interaction with the dodecameric portal protein, which stabilizes the structure of gp4 and suppresses unfolded gp4 from irreversibly aggregating in the Salmonella milieu. The structural stabilization of gp4 is accompanied by the concomitant oligomerization of the protein to form a ring of 12 subunits bound to the lower end of the portal ring. Themore » interaction of gp4 with portal protein is complex and likely involves the distinct binding of two non-equivalent sets of six gp4 proteins. Binding of the first set of six gp4 equivalents to dodecameric portal protein yields a gp(1){sub 12}:gp(4){sub 6} assembly intermediate, which is stably populated at 30 {sup o}C and can be resolved by native gel electrophoresis. The final product of the assembly reaction is a bi-dodecameric gp(1){sub 12}:gp(4){sub 12} complex, which appears hollow by electron microscopy, suggesting that gp4 does not physically plug the DNA entry/exit channel, but acts as a structural adaptor for the other tail accessory factors: gp10 and gp26.« less

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
930227
Report Number(s):
BNL-80902-2008-JA
Journal ID: ISSN 0022-2836; JMOBAK; TRN: US200822%%1406
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Molecular Biology; Journal Volume: 363
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; ADHESION; AGGLOMERATION; BACTERIOPHAGES; CELL WALL; CLOSURES; DNA; ELECTRON MICROSCOPY; ELECTROPHORESIS; GELS; HOST; IN VITRO; INJECTION; INTERACTIONS; PROTEINS; RANGE; RINGS; SALMONELLA; SOLUTIONS; STABILITY; STABILIZATION; YIELDS; national synchrotron light source

Citation Formats

Olia,A., Al-Bassam, J., Winn-Stapley, D., Joss, L., Casjens, S., and Cingolani, G. Binding-induced Stabilization and Assembly of the Phage P22 Tail Accessory Factor gp4. United States: N. p., 2006. Web. doi:10.1016/j.jmb.2006.08.014.
Olia,A., Al-Bassam, J., Winn-Stapley, D., Joss, L., Casjens, S., & Cingolani, G. Binding-induced Stabilization and Assembly of the Phage P22 Tail Accessory Factor gp4. United States. doi:10.1016/j.jmb.2006.08.014.
Olia,A., Al-Bassam, J., Winn-Stapley, D., Joss, L., Casjens, S., and Cingolani, G. Sun . "Binding-induced Stabilization and Assembly of the Phage P22 Tail Accessory Factor gp4". United States. doi:10.1016/j.jmb.2006.08.014.
@article{osti_930227,
title = {Binding-induced Stabilization and Assembly of the Phage P22 Tail Accessory Factor gp4},
author = {Olia,A. and Al-Bassam, J. and Winn-Stapley, D. and Joss, L. and Casjens, S. and Cingolani, G.},
abstractNote = {To infect and replicate, bacteriophage P22 injects its 43 kbp genome across the cell wall of Salmonella enterica serovar Typhimurium. The attachment of phage P22 to the host cell as well as the injection of the viral DNA into the host is mediated by the virion's tail complex. This 2.8 MDa molecular machine is formed by five proteins, which include the portal protein gp1, the adhesion tailspike protein gp9, and three tail accessory factors: gp4, gp10, gp26. We have isolated the tail accessory factor gp4 and characterized its structure and binding interactions with portal protein. Interestingly, gp4 exists in solution as a monomer, which displays an exceedingly low structural stability (T{sub m} 34 {sup o}C). Unfolded gp4 is prone to aggregation within a narrow range of temperatures both in vitro and in Salmonella extracts. In the virion the thermal unfolding of gp4 is prevented by the interaction with the dodecameric portal protein, which stabilizes the structure of gp4 and suppresses unfolded gp4 from irreversibly aggregating in the Salmonella milieu. The structural stabilization of gp4 is accompanied by the concomitant oligomerization of the protein to form a ring of 12 subunits bound to the lower end of the portal ring. The interaction of gp4 with portal protein is complex and likely involves the distinct binding of two non-equivalent sets of six gp4 proteins. Binding of the first set of six gp4 equivalents to dodecameric portal protein yields a gp(1){sub 12}:gp(4){sub 6} assembly intermediate, which is stably populated at 30 {sup o}C and can be resolved by native gel electrophoresis. The final product of the assembly reaction is a bi-dodecameric gp(1){sub 12}:gp(4){sub 12} complex, which appears hollow by electron microscopy, suggesting that gp4 does not physically plug the DNA entry/exit channel, but acts as a structural adaptor for the other tail accessory factors: gp10 and gp26.},
doi = {10.1016/j.jmb.2006.08.014},
journal = {Journal of Molecular Biology},
number = ,
volume = 363,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}