ARTICLE Complete 1 H, 13 C and 15 N NMR assignments for donor-strand complemented AafA, the major pilin of aggregative adherence fimbriae (AAF/II) from enteroaggregative E. coli Yi Yang • Andrea A. Berry • Wei-Chao Lee • James A. Garnett • Jan Marchant • Jonathan A. Levine • Peter J. Simpson • Sarah A. Fogel • Kristen M. Varney • Steven J. Matthews • James P. Nataro • Keith G. Inman Received: 1 April 2010 / Accepted: 2 August 2010 / Published online: 17 August 2010 Ó US Government 2010 Abstract Aggregative adherence fimbriae (AAF) are the primary adhesive factors of enteroaggregative Escherichia coli (EAEC) and are required for intestinal colonization. They mediate binding to extracellular matrix proteins of the enteric mucosa and display proinflammatory effects on epithelial cells in vitro. Among the simplest of bacterial fimbriae, these passive hairlike appendages are composed primarily of a single 16-kDa structural and adhesive sub- unit, AafA. Oligomerization occurs by incorporating the N-terminal strand of each AafA subunit into an otherwise incomplete b-sheet of an adjacent AafA subunit. We have engineered a highly soluble AafA monomer by positioning the N-terminal ‘‘donor strand’’ at the C-terminus, following a turn and short linker that were introduced to allow access of the donor strand to the recipient cleft of the same sub- unit. The resulting ‘‘donor-strand complemented’’ AafA subunit, or AafA-dsc folds autonomously, is monodisperse in solution, and yields high quality NMR spectral data. Here, we report the 1 H, 13 C, and 15 N chemical shift assignments for AafA-dsc. Keywords AafA Á Aggregative adherence fimbriae Á Adhesin Á Donor strand Á Enteroaggregative Á NMR resonance assignment Biological context Enteroaggregative Escherichia coli (EAEC) are a clinically important cause of diarrhea in both developing and industrialized countries. Infection can lead to watery diar- rhea that is often persistent and inflammatory (Okeke and Nataro 2001). AAF-mediated attachment to host epithe- lium is a required first step in the infection process. The four known AAF alleles, AAF/I through AAF/IV share little homology and are antigenically distinct, yet all four have been implicated in mediating the same ‘‘stacked brick’’ pattern of HEp-2 cell adherence that defines the enteroaggregative pathotype. Studies of AAF/II mutants suggest that they have important roles in pathogenesis including induction of IL-8 release, disruption of tight junctions, and binding to extracellular matrix proteins (Farfan et al. 2008; Harrington et al. 2005). The major structural subunit (or pilin) of AAF/II is the protein AafA (GenBank: AAB82330.1), which is also the principal adhesin of EAEC strains expressing this allele. AafA has been shown to bind fibronectin, laminin, and type IV col- lagen in vitro but not BSA or type I collagen. Evidence Y. Yang Á W.-C. Lee Á J. A. Garnett Á J. Marchant Á P. J. Simpson Á S. J. Matthews Division of Molecular Biosciences, Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, UK A. A. Berry Á J. A. Levine Á S. A. Fogel Á J. P. Nataro Division of Infectious Diseases and Tropical Pediatrics, University of Maryland School of Medicine, Center for Vaccine Development, 685 W. Baltimore St. Room 480, Baltimore, MD 21201, USA K. M. Varney Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 685 W. Baltimore St. Room 480, Baltimore, MD 21201, USA K. G. Inman (&) Department of Clinical Investigation, Walter Reed Army Medical Center, Building 7 Room 203, 6900 Georgia Avenue, NW, Washington, DC 20307, USA e-mail: inman.kg@gmail.com 123 Biomol NMR Assign (2011) 5:1–5 DOI 10.1007/s12104-010-9252-7