Adhesins pilus

Lindberg, F., Lund, B., Johansson, L., and Normark, S. (1987). Localization of the receptor-binding protein adhesin at the tip of the bacterial pilus. Nature 328,84-87. 

Microbial pathogens utilize different types of lectins for targeting the glycans on the surface of host cells. Many bacteria are covered with pili or fimbriae that contain a very special class of lectins known as adhesins because they play a role in attachment to epithelial cells. These lectins are monomeric and comprise only one binding site. Because the adhesins are repeated on the pilus, a larger number of adhesins on the bacterial surface create multivalent interaction with the host glycans. 

In order to comprehend the adhesion properties of piliated bacteria, it is necessary to acquire detailed information not only about the biophysical properties of individual pili under various conditions, in particular their behavior in regions II and III, but also the adhesin on the tip of the pilus. Moreover, to understand the unfolding and refolding properties of the pilus rod a good knowledge about the properties of individual bonds exposed to strain/stress is needed. A full understanding of adhesion properties of piliated bacteria requires finally knowledge about how several pili cooperate to deal with an external force. 

A pilus will detach from its receptor on the host cell whenever the adhesin bond opens. As was shown by (18.1), also the opening rate for the adhesin (Ad) bond, depends exponentially on the force to which it is exposed. 

Since the adhesin is located on the tip of the pilus, the force to which it is exposed is that exerted by the rod, which for a single pilus attachment is equal to the external force. 

Streptococcus pneumoniae Pilus adhesin RrgA Integrin I collagen recognition 2WW8 119... 

The in vitro flocculation of the yeast Kluyveromyces bulgaricus was inhibited by the branched thiocyclodextrin 64 (Scheme 15) with the same efficiency as the best known ligand [45]. On the other hand, the 4-thiogalabioside 90 (Scheme 18) has been shown to be ten times less recognized than its oxygen analog by a bacterial pilus adhesin [48]. 

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