Ehrlichia chaffeensis tandem repeat proteins and Ank200 are type 1 secretion system substrates related to the repeats-in-toxin exoprotein family.

"Conflict of Interest Statement The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest."

"We acknowledge Lutz Schmitt and Patrick Bakkes for kindly providing pHlyBD and pHlyAc plasmids and CGSC Yale for E. coli strains BW25113 and CAG12184 used in this study. We are grateful to Tian Luo and Xiaofeng Zhang for constructing some plasmids used in this study. We thank Jason Carlyon for many invaluable discussions and David Walker and Xue-jie Yu for reviewing the manuscript and providing helpful suggestions. The Hooykaas lab was supported by a TOP grant from Chemical Sciences of the Netherlands Organization for Scientific Research (NWO). This work was supported by National Institute of Allergy and Infectious Diseases (AI 071145)."