title: Structural insight of a concentration-dependent mechanism by which YdiV inhibits Escherichia coli flagellum biogenesis and motility.
abstract: YdiV is a negative regulator of cell motility. It interacts with FlhD(4)C(2) complex, a product of flagellar master operon, which works as the transcription activator of all other flagellar operons. Here, we report the crystal structures of YdiV and YdiV(2)-FlhD(2) complex at 1.9 Å and 2.9 Å resolutions, respectively. Interestingly, YdiV formed multiple types of complexes with FlhD(4)C(2). YdiV(1)-FlhD(4)C(2) and YdiV(2)-FlhD(4)C(2) still bound to DNA, while YdiV(3)-FlhD(4)C(2) and YdiV(4)-FlhD(4)C(2) did not. DNA bound FlhD(4)C(2) through wrapping around the FlhC subunit rather than the FlhD subunit. Structural analysis showed that only two peripheral FlhD subunits were accessible for YdiV binding, forming the YdiV(2)-FlhD(4)C(2) complex without affecting the integrity of ring-like structure. YdiV(2)-FlhD(2) structure and the negative staining electron microscopy reconstruction of YdiV(4)-FlhD(4)C(2) suggested that the third and fourth YdiV molecule bound to the FlhD(4)C(2) complex through squeezing into the ring-like structure of FlhD(4)C(2) between the two internal D subunits. Consequently, the ring-like structure opened up, and the complex lost DNA-binding ability. Thus, YdiV inhibits FlhD(4)C(2) only at relatively high concentrations.
authors.affiliation: State Key Laboratory of Microbial Technology, Shandong University, Jinan 250100, China.
authors.forename: Bingqing
authors.initials: B
authors.lastname: Li
authors.forename: Ning
authors.initials: N
authors.lastname: Li
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.forename: Liming
authors.initials: L
authors.lastname: Guo
authors.forename: Yan
authors.initials: Y
authors.lastname: Huang
authors.forename: Xiuhua
authors.initials: X
authors.lastname: Liu
authors.forename: Tiandi
authors.initials: T
authors.lastname: Wei
authors.forename: Deyu
authors.initials: D
authors.lastname: Zhu
authors.forename: Cuilan
authors.initials: C
authors.lastname: Liu
authors.forename: Hongfang
authors.initials: H
authors.lastname: Pan
authors.forename: Sujuan
authors.initials: S
authors.lastname: Xu
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Wang
authors.forename: Lichuan
authors.initials: L
authors.lastname: Gu
mesh_terms: D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004269:DNA, Bacterial / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D005407:Flagella / Q000378:metabolism; D008958:Models, Molecular; D009068:Movement; D009154:Mutation; D011485:Protein Binding; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D015534:Trans-Activators / Q000737:chemistry* / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D021122:Protein Subunits; D015534:Trans-Activators; C577842:YdiV protein, E coli; C090552:flhC protein, E coli; C090553:flhD protein, E coli