2RJZ

Crystal structure of the type 4 fimbrial biogenesis protein PilO from Pseudomonas aeruginosa

Summary for 2RJZ

• Entry DOI: 10.2210/pdb2rjz/pdb
• Descriptor: PilO protein, SULFATE ION (3 entities in total)
• Functional Keywords: structural genomics, unknown function, psi-2, protein structure initiative, new york sgx research center for structural genomics, nysgxrc
• Biological source: Pseudomonas aeruginosa
• Total number of polymer chains: 2
• Total formula weight: 33271.67

Authors

Bonanno, J.B.,Freeman, J.,Bain, K.T.,Chang, S.,Ozyurt, S.,Smith, D.,Wasserman, S.,Sauder, J.M.,Burley, S.K.,Almo, S.C.,New York SGX Research Center for Structural Genomics (NYSGXRC) (deposition date: 2007-10-16, release date: 2007-11-06, Last modification date: 2024-02-21)

Primary citation

Sampaleanu, L.M.,Bonanno, J.B.,Ayers, M.,Koo, J.,Tammam, S.,Burley, S.K.,Almo, S.C.,Burrows, L.L.,Howell, P.L.
Periplasmic domains of Pseudomonas aeruginosa PilN and PilO form a stable heterodimeric complex.
J.Mol.Biol., 394:143-159, 2009

PubMed Abstract: Type IV pili (T4P) are bacterial virulence factors responsible for attachment to surfaces and for twitching motility, a motion that involves a succession of pilus extension and retraction cycles. In the opportunistic pathogen Pseudomonas aeruginosa, the PilM/N/O/P proteins are essential for T4P biogenesis, and genetic and biochemical analyses strongly suggest that they form an inner-membrane complex. Here, we show through co-expression and biochemical analysis that the periplasmic domains of PilN and PilO interact to form a heterodimer. The structure of residues 69-201 of the periplasmic domain of PilO was determined to 2.2 A resolution and reveals the presence of a homodimer in the asymmetric unit. Each monomer consists of two N-terminal coiled coils and a C-terminal ferredoxin-like domain. This structure was used to generate homology models of PilN and the PilN/O heterodimer. Our structural analysis suggests that in vivo PilN/O heterodimerization would require changes in the orientation of the first N-terminal coiled coil, which leads to two alternative models for the role of the transmembrane domains in the PilN/O interaction. Analysis of PilN/O orthologues in the type II secretion system EpsL/M revealed significant similarities in their secondary structures and the tertiary structures of PilO and EpsM, although the way these proteins interact to form inner-membrane complexes appears to be different in T4P and type II secretion. Our analysis suggests that PilN interacts directly, via its N-terminal tail, with the cytoplasmic protein PilM. This work shows a direct interaction between the periplasmic domains of PilN and PilO, with PilO playing a key role in the proper folding of PilN. Our results suggest that PilN/O heterodimers form the foundation of the inner-membrane PilM/N/O/P complex, which is critical for the assembly of a functional T4P complex.

PubMed: 19857646
DOI: 10.1016/j.jmb.2009.09.037

Experimental method

X-RAY DIFFRACTION (2.2 Å)