Zipping into cells

The bacteria Staphylococcus aureus and Streptococcus pyogenes use fibronectin-binding proteins (FnBPs) anchored in their cell walls to adhere and invade host cells, but how the largely unstructured Fn-binding repeats of bacterial proteins recognize the host fibronectin has been unclear. In the May 8 Nature, Ulrich Schwarz-Linek and colleagues from University of Oxford, show that pathogenic bacteria attach to human fibronectin through a tandem β-zipper (Nature, 423:177-181, May 8, 2003).

Schwarz-Linek et al. used nuclear magnetic resonance spectroscopy to analyze the structure of a streptococcal (S. dysgalactiae) FnBP peptide (B3) in complex with the fibronectin module pair ¹F1²F1. They observed that ¹F1- and ²F1-binding motifs in B3 form additional antiparallel β-strands on sequential F1 modules, suggesting the formation of a tandem β-zipper. In addition, sequence analyses of larger regions of FnBPs from S. pyogenes and S. aureus revealed a repeating pattern...