2LC4: Solution Structure of PilP from Pseudomonas aeruginosa

Type IVa pili are bacterial nanomachines required for colonization of surfaces, but little is known about the organization of proteins in this system. The Pseudomonas aeruginosa pilMNOPQ operon encodes five key members of the transenvelope complex facilitating pilus function. While PilQ forms the outer membrane secretin pore, the functions of the inner membrane-associated proteins PilM/N/O/P are less well defined. Structural characterization of a stable C-terminal fragment of PilP (PilP(Delta71)) by NMR revealed a modified beta-sandwich fold, similar to that of Neisseria meningitidis PilP, although complementation experiments showed that the two proteins are not interchangeable likely due to divergent surface properties. PilP is an inner membrane putative lipoprotein, but mutagenesis of the putative lipobox had no effect on the localization and function of PilP. A larger fragment, PilP(Delta18-6His), co-purified with a PilN(Delta44)/PilO(Delta51) heterodimer as a stable complex that eluted from a size exclusion chromatography column as a single peak with a molecular weight equivalent to two heterotrimers with 1:1:1 stoichiometry. Although PilO forms both homodimers and PilN-PilO heterodimers, PilP(Delta18-6His) did not interact stably with PilO(Delta51) alone. Together these data demonstrate that PilN/PilO/PilP interact directly to form a stable heterotrimeric complex, explaining the dispensability of PilP's lipid anchor for localization and function.
PDB ID: 2LC4Download
MMDB ID: 95831
PDB Deposition Date: 2011/4/22
Updated in MMDB: 2011/12
Experimental Method:
solution nmr
Source Organism:
Similar Structures:
Biological Unit for 2LC4: monomeric; determined by author
Molecular Components in 2LC4
Label Count Molecule
Protein (1 molecule)
Pilp Protein
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB