E. Hoiczyk et al., Structure and sequence analysis of Yersinia YadA and Moraxella UspAs reveal a novel class of adhesins, EMBO J, 19(22), 2000, pp. 5989-5999
The non-fimbrial adhesins, YadA of enteropathogenic Yersinia species, and U
spA1 and UspA2 of Moraxella catarrhalis, are established pathogenicity fact
ors. In electron micrographs, both surface proteins appear as distinct 'lol
lipop'-shaped structures forming a novel type of surface projection on the
outer membranes. These structures, amino acid sequence analysis of these mo
lecules and yadA gene manipulation suggest a tripartite organization: an N-
terminal oval head domain is followed by a putative coiled-coil rod and ter
minated by a C-terminal membrane anchor domain. In YadA, the head domain is
involved in autoagglutination and binding to host cells and collagen. Anal
ysis of the coiled-coil segment of YadA revealed unusual pentadecad repeats
with a periodicity of 3.75, which differs significantly from the 3.5 perio
dicity found in the Moraxella UspAs and other canonical coiled coils. These
findings predict that the surface projections are formed by oligomers cont
aining right- (Yersinia) or left-handed (Moraxella) coiled coils, Strikingl
y, sequence comparison revealed that related proteins are found in many pro
teobacteria, both human pathogenic and environmental species, suggesting a
common role in adaptation to specific ecological niches.