Chemistry Reference
In-Depth Information
17
Bacterial and Viral Lectins
Jan Holgersson , Anki Gustafsson , and Stefan Gaunitz
The preceding chapters illustrated that cell-surface glycans are ideal to store bio-
logical information, and have described their structural complexity and biosynthe-
sis. Then, it was illustrated how well glycans interact with receptors (for defi nition
of the term 'lectin', see Chapter 15.3, with principles explained in Chapter 13 and
crystal structures shown in Chapter 16). What is timely now is to apply this knowl-
edge to the fi rst step in infection and provide information on bacterial/viral
lectins.
In this chapter, lectins of bacteria and viruses are described with regard to their
structural organization, carbohydrate specifi city and distribution between species.
Infectious diseases caused by bacteria and viruses involving particular lectin are
briefl y mentioned. In addition, carbohydrate-binding bacterial toxins are discussed
to illustrate versatility of lectin functions. In the last part of this chapter, carbohy-
drate-based anti-infectives on the market as well as under development are
described. The importance of multivalency for high-avidity binding of carbohy-
drate-based inhibitors (please see Chapter 4 for synthetic aspects of glycoden-
drimers and also applications), and how it can be accomplished, is discussed.
17.1
Bacterial Lectins
Bacterial lectins exist in different forms. They may be presented at the tip and/or
along the shaft of a fi mbriae or pili, they can be expressed directly on the bacterial
surface and they can be secreted as toxins. Their common denominator, however,
seems to be to facilitate host cell entry and to promote infection. The existence of
bacterial lectins has been known since 1902 (please see Table 15.1), but their full
complexity with regard to carbohydrate specifi city (for details on how to determine
lectin specifi city, please see Chapters 13
and
14) and its infl uence on host cell
infection and pathogenicity are being unraveled. Table 17.1 lists bacterial lectins
and their carbohydrate specifi city together with diseases caused by bacterial
infection.
