400 μL of each RG7112 nmr suspension was adsorbed on a nitrocellulose membrane (Hybond ECL Nitrocellulose, Amersham) via dot-blot equipment (MiniFold®, Schleicher & Schuell) and treated overnight with blocking solution (1x Tris-buffered saline (TBS) pH 8, 5% non-fat dry milk w/v). The blot was washed three times with 1x TBS and incubated with antiserum to M13 gp8, to T7 or to HA tag, respectively. The presence of gp9 variants was analysed with a secondary peroxidase-coupled antibody by chemoluminescence. Immunogold labelling of M13gp9 variant phage for TEM For testing the exposure of an antigenic epitope 50 μL of

each phage stock solution (about 1011 phage/mL) of M13gp9-DT7 and BYL719 ic50 M13gp9-DHA was incubated with 1 × TBS containing 0.1% BSA for 30 min to avoid unspecific binding of the primary antibody to the sample. Each sample was then incubated with the respective serum (diluted 1:20 in 1x TBS) for 1 h. Then, protein A coupled immunogold particles (Protein A – 20 nm colloidal gold, Sigma-Aldrich) was added 1:20 in 1x TBS for 1 h. After immunogold labelling, 10 μL of

the phage stock solution was adsorbed on carbon-coated copper grids (Athene 200, Plano, Wetzlar/Germany) that had been glow discharged shortly before use [21]. The suspensions were allowed to adsorb for 5 min, unbound material was removed by touching the grid to filter paper. The grid was then selleck chemical washed by touching the surface of a drop of distilled water for 2 sec. The excess water was removed by touching the grid to filter paper. A drop (5 μL) of 5% phosphotungstic acid (pH 7) was then applied to the grid and after 30 sec the excess stain was removed by touching the grid to a drop (50 μL) of ddH20 for 2 sec. The excess liquid was drawn off with filter paper. The grid was dried at room temperature and examined by electron microscopy. References 1. Marciano DK, Russel M, Simon S: Assembling filamentous phage occlude pIV channels. Proc Natl Acad Sci

2001 98:9359–9364. 2. Haigh NG, Webster RE: The pI and pXI assembly proteins serve separate and essential roles in filamentous phage assembly. J Mol Biol 1999 293:1017–1027. 3. Endemann H, Model P: Location of filamentous phage minor coat proteins in phage and in infected cells. J Mol Biol 1995 250:496–506. Edoxaban 4. Samuelson JC, Chen M, Jiang F, Möller I, Wiedmann M, Kuhn A, Phillips GJ, Dalbey RE: YidC mediates membrane protein insertion in bacteria. Nature 2000 406:637–641. 5. Stiegler N, Dalbey RE, Kuhn A: M13 procoat protein insertion into YidC and SecYEG proteoliposomes and liposomes. J Mol Biol 2011 406:362–370. 6. Kuhn A, Wickner W: Conserved residues of the leader peptide are essential for cleavage by leader peptidase. J Biol Chem 1985, 260:15914–15918.PubMed 7. Haigh NG, Webster RE: The major coat protein of filamentous bacteriophage f1 specifically pairs in the bacterial cytoplasmic membrane. J Mol Biol 1998, 279:19–29.PubMedCrossRef 8.