Fig 1.

Schematic representation of the five Sca proteins whose genes were identified in the O. tsutsugamushi genome and demonstration of purified bacterial antigens. (A) Domain structures were predicted using SMART (simple modular architecture research tool [http://smart.embl-heidelberg.de/]). The amino acid positions (indicated by numbers) are based on the sequences from the Boryong strain. The green lines indicate the cloned region for protein expression, and the blue lines show the passenger domains used for sequence analysis after PCR amplification. SP, signal peptide; RPT, internal repeat sequence; TM, transmembrane domain; AT, autotransporter domain; AA, amino acids. (B) The bacterial antigens were cloned into the pET28a expression vector by use of the specific primers summarized in Table 1 and were expressed in E. coli. The His-tagged proteins were purified using Ni-NTA His-binding resin and then visualized by SDS-PAGE and Coomassie brilliant blue staining.