PubMed · 1905978
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S Falkow. 1991-06-28. Bacterial entry into eukaryotic cells.. https://doi.org/10.1016/0092-8674(91)90003-h
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Putative adhesins were predicted by computer analysis of the Treponema pallidum genome. Two treponemal proteins, Tp0155 and Tp0483, demonstrated specific attachment to fibronectin, blocked bacterial adherence to fibronectin-coated slides, and supported attachment of fibronectin-producing mammalian cells. These results suggest Tp0155 and Tp0483 are fibronectin-binding proteins mediating T. pallidum-host interactions.
Pneumococcal surface adhesin A (PsaA) is one of the common protein antigens of Streptococcus pneumoniae investigated as a possible vaccine candidate on the basis of studies in experimental animal models. The relation between the serum anti-PsaA concentration collected at 6, 12 and 18 months of age and the risk of pneumococcal carriage and acute otitis media (AOM) in the following 6 months was evaluated in 329 children of the Finnish Otitis Media (FinOM) Cohort Study. A higher anti-PsaA concentration at all three time points studied was found to predict a higher risk of pneumococcal carriage 6 months later. A higher anti-PsaA concentration at 6 months also predicted a higher risk of pneumococcal AOM during the following 6 months (RR 1.51, 95% CI 1.24-1.83), whereas a higher anti-PsaA concentration at 12 or 18 months seemed to decrease the risk of pneumococcal AOM (RR 0.94 [95% CI 0.80-1.09] and RR 0.88 [95% CI 0.73-1.07], respectively). These relations remained the same when concomitant risk factors for pneumococcal AOM were included in the models. Previous pneumococcal AOM was the most important risk factor for a subsequent pneumococcal AOM (RR 5.93 [95% CI 2.87-12.3], RR 2.2 [95% CI 1.21-4.00], and RR 3.3 [95% CI 1.72-6.32] during the three periods).
Methyltransferases (MTases) from the Erm family catalyze S-adenosyl-L-methionine-dependent modification of a specific adenine residue in bacterial 23S rRNA, thereby conferring resistance to clinically important macrolide, lincosamide and streptogramin B antibiotics. Despite the available structural data and functional analyses on the level of the RNA substrate, still very little is known about the mechanism of rRNA:adenine-N(6) methylation. Only predictions regarding various aspects of this reaction have been made based on the analysis of the crystal structures of methyltransferase ErmC' (without the RNA) and their comparison with the crystallographic and biochemical data for better studied DNA:m(6)A MTases. To validate the structure-based predictions of presumably essential residues in the catalytic pocket of ErmC', we carried out the site-directed mutagenesis and studied the function of the mutants in vitro and in vivo. Our results indicate that the active site of rRNA:m(6)A MTases is much more tolerant to amino acid substitutions than the active site of DNA:m(6)A MTases. Only the Y104 residue implicated in stabilization of the target base was found to be indispensable. Remarkably, the N101 residue from the "catalytic" motif IV and two conserved residues that form the floor (F163) and one of the walls (N11) of the base-binding site are not essential for catalysis in ErmC'. This somewhat surprising result is discussed in the light of the available structural data and in the phylogenetic context of the Erm family.