Bacterial Adhesion Chemistry, Biology and Physics
Adhesion plays a major role in the bacterial lifestyle. Bacteria can adhere to organic and inorganic surfaces, to each other, and of course to host cells during pathogenesis. The focus of this book is: how are such adhesion phenomena best studied? Microbi
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Structure and Biology of Trimeric Autotransporter Adhesins Andrzej Łyskowski, Jack C. Leo, and Adrian Goldman
Abstract Trimeric autotransporter adhesins (TAAs) are a family of secreted Gramnegative bacterial outer membrane (OM) proteins. These obligate homotrimeric proteins share a common molecular organisation, consisting of a N-terminal “passenger” domain followed by a C-terminal translocation unit/membrane anchor. All described TAAs act as adhesins. The passenger domain is responsible for specific adhesive and other activities of the protein and has a modular architecture. Its globular head domain(s), where ligands often bind, are projected away from the bacterial surface by an extended triple α-helical coiled coil stalk attached to the β-barrel anchor. The head domains appear to be constructed from a limited set of subdomains. The β-barrel anchor is the only part of the protein strictly conserved between family members. It appears that the extracellular export of the passenger does not require an external energy source or auxiliary proteins, though recent data indicate that an OM complex (the Bam complex) is involved in passenger domain secretion. The ability to bind to a variety of host molecules such as collagen, fibronectin, laminin or cell surface receptors via a structurally diverse elements suggests that TAAs have evolved a unique mechanism which closely links structure to folding and function.
9.1 Introduction Although the vast majority of symbiotic bacteria are either harmless or beneficial to their (human) hosts, one of the most evident, negative results of human interaction with the surrounding ocean of microbial life is the occurrence of diseases, some life-threatening. Gram-negative infectious bacteria have caused very high levels of morbidity and mortality, such as Yersinia pestis, the causative agent of
A. Goldman (B) Institute of Biotechnology, Viikinkaari 1, University of Helsinki, FIN-00014 Helsinki, Finland e-mail: [email protected] D. Linke, A. Goldman (eds.), Bacterial Adhesion, Advances in Experimental Medicine and Biology 715, DOI 10.1007/978-94-007-0940-9_9, C Springer Science+Business Media B.V. 2011
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bubonic plague, which eradicated up to 40% of the population of Europe in the fourteenth century (Perry and Fetherston, 1997). Even today, septicemic melioidosis, caused by Burkholderia pseudomallei which is endemic in Southeast Asia, has a greater than 10% mortality rate even with treatment (e.g. Warner et al., 2007). The introduction of effective antibiotics in the twentieth century, starting with the discovery of penicillin in 1928 (Fleming, 1929), resulted in a huge decrease in mortality due to bacterial infections. However, the emergence of multiply antibiotic-resistant bacterial strains and the steadily growing threat of bioterrorism have increased interest in what were only recently considered defeated diseases. To successfully colonize the host, bacteria need to establish and maintain an association with host tissues. Various secreted vi
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