A. Rakin et al., THE PESTICIN RECEPTOR OF YERSINIA-ENTEROCOLITICA - A NOVEL VIRULENCE FACTOR WITH DUAL FUNCTION, Molecular microbiology, 13(2), 1994, pp. 253-263
The iron-repressible outer membrane protein FyuA of Yersinia enterocol
itica operates as a receptor with dual function: (i) as a receptor for
the Y. pestis bacteriocin pesticin, and (ii) as a receptor for yersin
labactin, a siderophore that is produced by mouse-virulent Y. enteroco
litica strains of biogroup IB. Cloning of the FyuA-encoding gene was a
chieved by mobilization of a genomic cosmid library of the pesticin-se
nsitive and mouse-virulent Y. enterocolitica 0:8 strain WA into the pe
sticin-resistant WA fyuA mutant and subsequent in vivo selection of tr
ansconjugants for the ability to survive and multiply in mice (phenoty
pe mouse virulence). The reisolated transconjugants which survived in
mice for 3 d harboured a unique cosmid and phenotypically were pestici
n sensitive. From this cosmid a 2650 bp Sall-Pstl fragment conferring
pesticin sensitivity was subcloned. Sequencing of this DNA fragment re
vealed a single open reading frame of 2022 bp, which encodes a deduced
polypeptide of 673 amino acids with a predicted molecular mass of 736
77 Da. Cleavage of a putative signal sequence composed of 22 amino aci
ds should lead to a mature protein of 651 amino acids with a molecular
mass of 71 368 Da. The open reading frame is preceded by a sequence w
hich shares homology with the postulated consensus Fur iron-repressor
protein-binding site. FyuA shows homology to other iron-regulated TonB
-dependent outer membrane proteins with receptor functions (e.g. BtuB,
CirA, FepA, lutA, FhuA, FoxA, FcuA). On the basis of multiple alignme
nt of amino acid sequences of FyuA and other TonB-dependent receptors,
a phylogenetic tree was constructed, demonstrating that FyuA probably
belongs to the citrate subfamily or represents a new subfamily of Ton
e-dependent receptors. Moreover, by complementation of the WA fyuA mut
ant by the cloned fyuA gene, yersiniabactin uptake and mouse virulence
were restored. These studies demonstrate that the cloned pesticin/yer
siniabactin receptor FyuA of Y. enterocolitica has the typical feature
s of iron-regulated TonB-dependent outer membrane receptors for sidero
phores and bacteriocins and is required for mouse virulence.