BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Talks.cam//talks.cam.ac.uk// X-WR-CALNAME:Talks.cam BEGIN:VEVENT SUMMARY:Host matrix-pathogen interactions and redox sensing\; tandem beta- zippers and "\;inside-out"\; protein-protein recognition. - Dr. J ennifer Potts University of York DTSTART:20101103T103000Z DTEND:20101103T113000Z UID:TALK27029@talks.cam.ac.uk CONTACT:Dr Alfonso De Simone DESCRIPTION:The interaction between Staphylococcus aureus and Streptococcu s pyogenes with the human plasma and extracellular matrix protein fibronec tin triggers bacterial invasion of host cells. This process has been propo sed to aid haematogenous dissemination of infection and evasion of the hos t immune system. We have used a range of biophysical techniques to define the binding sites in the host and bacterial proteins and the structure of the complex that forms. In a highly unusual mechanism of protein-protein r ecognition\, the bacterial peptide undergoes a transition from an intrinsi cally disordered state\, to an extended anti-parallel β-strand along the triple-stranded β-sheets of up to five sequential fibronectin modules (1- 3). A dissection of the S. aureus and S. pyogenes fibronectin-binding prot eins\, based on the tandem β-zipper and confirmed using isothermal titrat ion calorimetry\, has identified multiple high affinity binding sites in b oth proteins (4\,5). \nIn a separate project\, we have been investigating a redox-sensing anti-sigma factor (RsrA) from Streptomyces coelicolor. We have determined the solution structures of the reduced and oxidized forms of RsrA. Comparison with the structures of homologous anti-sigma factors i n complex with their cognate sigma factors suggests another unusual mechan ism of protein-protein recognition.\n\n1. Schwarz-Linek et al. (2003) Natu re 423\, 177-181\n2. Bingham et al. (2008) Proc. Natl Acad. Sci. USA 105\, 12254-12258\n3. Atkin et al.\, (2010) J. Biol. Chem. (in press)\n4. Schwa rz-Linek et al. (2004) J. Biol. Chem. 279\, 39017-39025\n5. Meenan et al. (2007) J. Biol. Chem. 282\, 25893-25902\n LOCATION:Unilever Lecture Theatre\, Department of Chemistry END:VEVENT END:VCALENDAR