Structural highlights
Function
[PAPD_ECOLX] Binds and caps interactive surfaces on pilus subunits to prevent them from participating in non-productive interactions. Facilitates the import of subunits into the periplasm. May facilitate subunit folding. Chaperone-subunit complexes are then targeted to the PapC outer membrane usher where the chaperone must uncap from the subunits. [PAPE_ECOLX] Repeated PapE subunits make up the thin (2 nm in diameter) tip fibrillum of the pilus. Subunits are arranged in a open helical conformation. Pili with a defective papE gene have low adhesive capacity or none; however, the binding property of the whole cell is not affected. Pili are polar filaments radiating from the surface of the bacterium to a length of 0.5-1.5 micrometers and numbering 100-300 per cell, and enable bacteria to colonize the epithelium of specific host organs.
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Periplasmic chaperones direct the assembly of adhesive, multi-subunit pilus fibers that play critical roles in bacterial pathogenesis. Pilus assembly occurs via a donor strand exchange mechanism in which the N-terminal extension of one subunit replaces the chaperone G(1) strand that transiently occupies a groove in the neighboring subunit. Here, we show that the chaperone primes the subunit for assembly by holding the groove in an open, activated conformation. During donor strand exchange, the subunit undergoes a topological transition that triggers the closure of the groove and seals the N-terminal extension in place. It is this topological transition, made possible only by the priming action of the chaperone that drives subunit assembly into the fiber.
Chaperone priming of pilus subunits facilitates a topological transition that drives fiber formation.,Sauer FG, Pinkner JS, Waksman G, Hultgren SJ Cell. 2002 Nov 15;111(4):543-51. PMID:12437927[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Sauer FG, Pinkner JS, Waksman G, Hultgren SJ. Chaperone priming of pilus subunits facilitates a topological transition that drives fiber formation. Cell. 2002 Nov 15;111(4):543-51. PMID:12437927
