4c47

Publication Abstract from PubMed

Trimeric Autotransporter Adhesins (TAAs) are important virulence factors of many gram-negative bacterial pathogens. TAAs form fibrous, adhesive structures on the bacterial cell surface. Their N-terminal, extracellular domains are exported through a C-terminal membrane pore; the insertion of the pore domain into the bacterial outer membrane follows the rules of beta-barrel transmembrane protein biogenesis and is dependent on the essential Bam complex. We have recently described the full fiber structure of SadA, a TAA of unknown function in Salmonella and other enterobacteria. In this work, we describe the structure and function of SadB, a small inner membrane lipoprotein. The sadB gene is located in an operon with sadA; orthologous operons are only found in enterobacteria, while other TAAs are not typically associated with lipoproteins. Strikingly, SadB is also a trimer, and its co-expression with SadA has a direct influence on SadA structural integrity. This is the first report of a specific export factor of a TAA, suggesting that at least in some cases, TAA autotransport is assisted by additional periplasmic proteins.

A Trimeric Lipoprotein assists in Trimeric Autotransporter Biogenesis in Enterobacteria.,Grin I, Hartmann MD, Sauer G, Hernandez Alvarez B, Schutz M, Madlung J, Macek B, Felipe-Lopez A, Hensel M, Lupas A, Linke D J Biol Chem. 2013 Dec 25. PMID:24369174^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.