P-fimbrial adhesin PapG (PapG) (PapG)

P-fimbrial adhesin PapG is a specialized lectin located at the distal tip of P pili, which are hair-like appendages expressed by uropathogenic Escherichia coli (UPEC). Its primary biological function is to mediate high-affinity binding to the Gal(alpha1-4)Gal carbohydrate moiety found on the P blood group antigens of human kidney epithelial cells [1]. This specific adherence is a prerequisite for the colonization of the upper urinary tract and is strongly associated with the pathogenesis of acute pyelonephritis and urosepsis [2]. The PapG protein exists in several molecular variants (Class I, II, and III), each with distinct receptor specificities that influence host range and tissue tropism [3]. Therapeutic interventions targeting PapG focus on anti-adhesion strategies, such as the use of small-molecule pilicides that inhibit the chaperone-usher assembly pathway or carbohydrate mimetics that block the adhesin's binding site [4]. By preventing bacterial attachment rather than killing the pathogen, these approaches aim to reduce the selective pressure for antibiotic resistance while effectively preventing infection [5]. Sources: [1] UniProt (P07110). [2] Wright et al. (2007), Structure of the PapGII adhesin-receptor complex, EMBO J. [3] Roberts et al. (1994), Molecular epidemiology of urinary tract infections, J. Infect. Dis. [4] Pinkner et al. (2006), Rationally designed pilicides and curlicides, PNAS. [5] Spaulding et al. (2017), Selective depletion of uropathogenic E. coli from the gut, Nature.

Other names

PapGP-fimbrial adhesinGal-Gal binding proteinPyelonephritis-associated pilus adhesinP-pili tip adhesin

Inhibition of the chaperone-usher assembly pathway or competitive blockade of the Gal(alpha1-4)Gal binding site.