Structure of the head of the Bartonella adhesin BadA

• Published in: PLoS pathogens Vol. 4; no. 8; p. e1000119
• Main Authors: Szczesny, Pawel, Linke, Dirk, Ursinus, Astrid, Bär, Kerstin, Schwarz, Heinz, Riess, Tanja M, Kempf, Volkhard A J, Lupas, Andrei N, Martin, Jörg, Zeth, Kornelius
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 08.08.2008; Public Library of Science (PLoS)
• Subjects: Adhesins, Bacterial - chemistry; Adhesion; Bartonella; Bartonella henselae; Bartonella henselae - chemistry; Binding sites; Biochemistry/Membrane Proteins and Energy Transduction; Biophysics/Experimental Biophysical Methods; Biophysics/Membrane Proteins and Energy Transduction; Biophysics/Structural Genomics; Computational Biology/Macromolecular Sequence Analysis; Computational Biology/Macromolecular Structure Analysis; Computational Biology/Protein Homology Detection; Computational Biology/Protein Structure Prediction; Crystal structure; Crystallography, X-Ray; Evolution, Molecular; Evolutionary Biology/Microbial Evolution and Genomics; Haemophilus; HIV; Human immunodeficiency virus; Infectious Diseases/Bacterial Infections; Mass spectrometry; Meningitis; Microbiology; Microbiology/Medical Microbiology; Microbiology/Microbial Evolution and Genomics; Moraxella; Neisseria; Protein Structure, Secondary - physiology; Protein Structure, Tertiary - physiology; Proteins; Proteobacteria; Yersinia
• ISSN: 1553-7374; 1553-7366; 1553-7374
• DOI: 10.1371/journal.ppat.1000119

Trimeric autotransporter adhesins (TAAs) are a major class of proteins by which pathogenic proteobacteria adhere to their hosts. Prominent examples include Yersinia YadA, Haemophilus Hia and Hsf, Moraxella UspA1 and A2, and Neisseria NadA. TAAs also occur in symbiotic and environmental species and presumably represent a general solution to the problem of adhesion in proteobacteria. The general structure of TAAs follows a head-stalk-anchor architecture, where the heads are the primary mediators of attachment and autoagglutination. In the major adhesin of Bartonella henselae, BadA, the head consists of three domains, the N-terminal of which shows strong sequence similarity to the head of Yersinia YadA. The two other domains were not recognizably similar to any protein of known structure. We therefore determined their crystal structure to a resolution of 1.1 A. Both domains are beta-prisms, the N-terminal one formed by interleaved, five-stranded beta-meanders parallel to the trimer axis and the C-terminal one by five-stranded beta-meanders orthogonal to the axis. Despite the absence of statistically significant sequence similarity, the two domains are structurally similar to domains from Haemophilus Hia, albeit in permuted order. Thus, the BadA head appears to be a chimera of domains seen in two other TAAs, YadA and Hia, highlighting the combinatorial evolutionary strategy taken by pathogens.