PilF Is an Outer Membrane Lipoprotein Required for Multimerization and Localization of the Pseudomonas aeruginosa Type IV Pilus Secretin
Type IV pili (T4P) are retractile appendages that contribute to the virulence of bacterial pathogens. PilF is a Pseudomonas aeruginosa lipoprotein that is essential for T4P biogenesis. Phenotypic characterization of a pilF mutant confirmed that T4P-mediated functions are abrogated: T4P were no longer present on the cell surface, twitching motility was abolished, and the mutant was resistant to infection by T4P retraction-dependent bacteriophage. The results of cellular fractionation studies indicated that PilF is the outer membrane pilotin required for the localization and multimerization of the secretin, PilQ. Mutation of the putative PilF lipidation site untethered the protein from the outer membrane, causing secretin assembly in both inner and outer membranes. T4P-mediated twitching motility and bacteriophage susceptibility were moderately decreased in the lipidation site mutant, while cell surface piliation was substantially reduced. The tethering of PilF to the outer membrane promotes the correct localization of PilQ and appears to be required for the formation of stable T4P. Our 2.0-A structure of PilF revealed a superhelical arrangement of six tetratricopeptide protein-protein interaction motifs that may mediate the contacts with PilQ during secretin assembly. An alignment of pseudomonad PilF sequences revealed three highly conserved surfaces that may be involved in PilF function.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
- Sponsoring Organization:
- Doe - Office Of Science
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 980390
- Report Number(s):
- BNL-93308-2010-JA; JOBAAY; TRN: US201015%%1775
- Journal Information:
- Journal of Bacteriology, Vol. 190, Issue 21; ISSN 0021-9193
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
ALIGNMENT
BACTERIOPHAGES
FRACTIONATION
FUNCTIONS
INTERACTIONS
LIPOPROTEINS
MEMBRANES
MUTANTS
MUTATIONS
PATHOGENS
PROTEINS
PSEUDOMONAS
SECRETIN
SURFACES
VIRULENCE
national synchrotron light source