title: In vitro observation of the molecular interaction between NodD and its inducer naringenin as monitored by fluorescence resonance energy transfer.
abstract: At initial stages in the Rhizobium legume symbiosis, most nodulation genes are controlled by NodD protein and plant inducers. Some genetic studies and other reports have suggested that NodD may be activated by its direct interaction with plant inducers. However, there has been no molecular evidence of such an inducing interaction. In this paper, we used fluorescence resonance energy transfer technique to see whether such an interaction exists between NodD and its activator, naringenin, in vitro. The tetracysteine motif (Cys-Cys-Pro-Gly-Cys-Cys) was genetically inserted into NodD to label NodD with 4',5'-bis(1,3,2-dithioarsolan-2-yl) fluorescein (FlAsH). Naringenin was labeled with fluorescein by chemical linking. In the fluorescence resonance energy transfer experiments in vitro, the fluorescence intensity of one acceptor, NodD(90R6)-FlAsH, increased by 13%. This suggests that NodD may directly interact with inducer naringenin in vitro and that the reaction centre is likely near hinge region 1 of NodD.
authors.affiliation: State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
authors.forename: Fengqing
authors.initials: F
authors.lastname: Li
authors.forename: Bihe
authors.initials: B
authors.lastname: Hou
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.forename: Zhujun
authors.initials: Z
authors.lastname: Yao
authors.forename: Guofan
authors.initials: G
authors.lastname: Hong
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D044950:Flavanones / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism*; D019793:Fluorescein / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer; D005456:Fluorescent Dyes / Q000378:metabolism; D066298:In Vitro Techniques; D015394:Molecular Structure; D009154:Mutation; D010957:Plasmids; D016961:Rhizobium leguminosarum / Q000235:genetics / Q000378:metabolism*; D013050:Spectrometry, Fluorescence
chemical_list: D001426:Bacterial Proteins; D044950:Flavanones; D005456:Fluorescent Dyes; C005273:naringenin; D019793:Fluorescein