coli lysate. GST-Cpn0859 co-purified with His- FlhA308-583, but not His-FliF35-341 or learn more His-FliF1-271 check details while GST alone did no co-purify with either. FliI and FlhA interact with T3S components Since Chlamydia have no apparent flagella,

we investigated whether the flagellar proteins FliI, FlhA and FliF interact with T3S components. Using bacterial-2-hybrid screening we found that FliI and FlhA interacted with CdsL, the putative T3S ATPase regulator and tethering protein, with a β-galactosidase activity of 874.3 ± 59.3 and 832 ± 23.3 units of activity, respectively. FliI also interacted with CopN, the putative T3S plug protein, with a β-galactosidase activity of 943.2 ± 74.2 units of activity. We also found that FlhA interacted with the putative YscU ortholog, CdsU, with a β-galactosidase activity of 779.9 ± 32.7 units of activity, as well as CdsL, with a β-galactosidase activity of 832.1 ± 23.3 units of activity (Table 1). To corroborate these findings we utilized GST pull-down assays and showed that GST-FliI interacted with CdsL and CopN, but not Cpn0706 (Figure 5A), and GST-FlhA co-purified with both CdsL and CdsU (Figure 5B). Control GST coated beads did not co-purify with CdsL, CopN or CdsU. Figure 5 Interaction of FliI and Anlotinib price FlhA with T3S components. A: Full length

GST-FliI was bound to glutathione beads and were used to pull down His-CdsL, His-CopN and His-Cpn0706. GST-FliI co-purified with both His-CdsL and His-CopN, but not His-Cpn0706. GST alone was not able to co-purify with any of the proteins. GST-FliI is shown as a loading control. B: GST-FlhA308-583 was bound to glutathione beads and used to pull down His-CdsL and His-Cpn0322. GST-FlhA308-583 co-purified with both CdsL and Cpn0322. GST alone did not co-purify with either protein. GST-FlhA308-583 is shown as a loading control. C: Discussion Sequencing of several Chlamydial genomes revealed a conserved set of flagellar orthologs, despite the fact that

C. pneumoniae lack a flagellum and are considered non-motile bacteria [22, 23]. Here we report an initial characterization of three annotated Ureohydrolase flagellar proteins of C. pneumoniae, FliI, FlhA and FliF, demonstrating ATPase activity of FliI and interactions between these flagellar orthologs. We have demonstrated that FliI hydrolyzes ATP in a linear, time-and dose-dependant manner, with optimal activity at a pH of 8.0 and a temperature of 37°C. FliI also interacts with the cytoplasmic domain of FlhA, while FlhA interacts with the C-terminal region of the FliF protein. No direct interaction of FliI and FliF was detected. Also, we have characterized an interaction of both FlhA and FliI with Cpn0859, a fourth unannotated protein. We also show that FliI interacts with CdsL and CopN, two T3S components, while FlhA interacts with CdsL and a third T3S component, CdsU. Collectively, this data suggests that the flagellar proteins of C.