The sequence encoding three nuclear localizing signals（NLSs）at the C-terminal of pthA,was amplified by PCR from the plasmid of Xanthomonas axonopodis pv.citri.and cloned into PET32a（＋）vector.The recombinant plasmid named pthA-NLS was identified by restriction digestion and sequence analysis.The sequence of the cloned NLSs had 99.9% of similarity with that of pthA in GenBank.The recombinant fusion protein was expressed in E.coli BL21（DE3）and analyzed by 12% SDS-PAGE.A 48 kD of recombinant fusion protein was purified with Ni^2＋-NTA resin....
