title: Improvement of Bacterial Two Hybrid System.
abstract: Bacterial two-hybrid system is a newly developed method for studying protein-protein interactions, especially for effects of the environmental factors on the interaction. In our studies of the effect of NH(4)( ) or oxygen on the NifL-NifA interaction, it was found that E.coli strain DHP1 cya(-), when transformed by T18-NifL together with T25-NifA, exhibited high activity of beta-galactosidase in the presence of NH(4)( ), and appeared as red colonies when grown in MacConkey/maltose agar. This indicated the direct interaction of NifL and NifA. However,similar phenomena were also shown in the case of the DHP1 cya(-) strain harboring T18-NifL or T25-NifL alone, respectively, without its interacting counterpart T25-NifA or T18-NifA. In this paper, a brief method is presented to detect the protein-protein interaction using direct assay of the adenylate cyclase, thus minimizing the false positives produced by the beta-galactosidase activity assay or MacConkey/maltose agar plating.
authors.affiliation: Laboratory of Molecular Genetics, Shanghai Institute of Plant Physiology, Shanghai Institute for Biological Sciences, the Chinese Academy of Sciences, Shanghai 200032, China. jbzhu@iris.sipp.ac.cn
authors.forename: Gong-Xian
authors.initials: GX
authors.lastname: Liao
authors.forename: Guan-Qiao
authors.initials: GQ
authors.lastname: Yu
authors.forename: Jia-Bi
authors.initials: JB
authors.lastname: Zhu