Analysis of chaperone function in vitro Effects of PpiD proteins on the thermal aggregation of citrate synthase were determined learn more according to [34]. Aggregation was monitored on a Hitachi F-4500 spectrofluorometer with both excitation and emission

wavelengths set to 500 nm at a spectral bandwidth of 2.5 nm. Data points were recorded every 0.5 s. Acknowledgements We thank C.A. Gross for providing strains and plasmids, D. Kahne and T. Silhavy for sharing strains, M. Ehrmann for the gift of plasmids and antibodies, and A. Charbit, E. Deuerling, B. Bukau, and K. Williams for providing antibodies. We also thank W. Kramer for helpful discussions. The work was supported by grants of the DFG to S.B. Electronic supplementary material Additional file 1: Similarity between the N-terminal region of PpiD and the chaperone modules of SurA and Trigger factor (TF). (A and B) The N-terminal region of PpiD shows sequence similarity with the N- and C-terminal regions of SurA (A, 25.2% identity) and TF (B, 19.9% identity), respectively. The sequence alignments were generated with CLUSTALW2 [63]. Gray shaded regions indicate the regions of high similarity that were initially identified with LALIGN [64] (31.1% (A) and 24.1% (B) identity, respectively). Identical amino acid residues are indicated by asterisks; conserved and semi-conserved

residues are marked with colons and dots, respectively. (C-E) CRM1 inhibitor Three-dimensional homology modeling suggests structural similarity of the N-terminal region of PpiD with the chaperone modules of SurA and TF. All structures were visualized in PyMol and are depicted in ribbon representation. (C) Comparative model structure of the N-terminal region of

PpiD (red colored) and the N-Ct chaperone module of SurA (blue colored) based on the sequence alignment shown in (A). The model was generated in the Swiss-Model workspace [65] using the structure coordinates of SurA (PDB 1m5y; [42]) as a template. Helices of the N-terminal region of SurA are numbered. A region of PpiD that corresponds to the C-terminal DNA ligase helix (“”C helix”") of SurA has not yet been identified. (D) Model structure of the N-terminal region of PpiD generated by the automatic program 3D-JIGSAW [66]. (E) Fold of the C-terminal chaperone domain of TF (PDB code 1w26; [41]). The region that shares similarity with PpiD is highlighted in red (corresponding to the gray shaded sequence in (B)). (PDF 257 KB) Additional file 2: Complementation of the growth defect of ppiD skp surA cells by wild-type PpiD and its PPIase domain mutants. Growth of the SurA-depletion strain P Llac-O1 -surA Δskp ppiD::kan (SB44961) carrying the empty vector pASK75 or plasmids encoding wild-type proteins and variants of SurA, Skp, and PpiD, respectively.