Journal Article

Structural insights into the regulatory mechanism of the Pseudomonas aeruginosa YfiBNR system

Liu, Tie-Zheng, Yang, Xuan, Xu, Min, Fan, Zusen, Zhou, Lei, Jiang, Tao, Yang, Xiu-An

2016

Overview

YfiBNR is a recently identified bis-（3＇-5＇）-cyclic dimeric GMP （c-di-GMP） signaling system in opportunistic pathogens. It is a key regulator of biofilm formation, which is correlated with prolonged persistence of infection and antibiotic drug resistance. In response to cell stress, YfiB in the outer membrane can sequester the pariplasmic protein YfiR, releasing its inhibition of YfiN on the inner membrane and thus provoking the diguanylate cyclase activity of YfiN to induce c-di-GMP production. However, the detailed regulatory mechanism remains elusive. Here, we report the crystal struc- tures of YfiB alone and of an active mutant YfiB^L43P complexed with YfiR with 2：2 stoichiometry. Structural analyses revealed that in contrast to the compact conformation of the dimeric YfiB alone, YfiB^L43P adopts a stretched conformation allowing activated YfiB to penebate the peptidoglycan （PG） layer and access YfiR. YfiBL43P shows a more compact PG-binding pocket and much higher PG binding affinity than wild-type YflB, suggesting a tight correlation between PG binding and YfiB activation. In addition, our crystallographic analyses revealed that YflR binds Vitamin B6 （VB6） or L-Trp at a YfiB-binding site and that both VB6 and L-Trp are able to reduce YfiBL43P-induced biofilm formation. Based on the structural and biochemical data, we propose an updated regulatory model of the YfiBNR system.

• Publisher: Higher Education Press,Springer Nature B.V,Oxford University Press
• Subject: Amino Acid Sequence / Bacterial Proteins - chemistry / Bacterial Proteins - genetics / Bacterial Proteins - metabolism / Binding Sites / Biochemistry / Biofilms / bioflim formation / Biomedical and Life Sciences / c-di-GMP / Cell Biology / Crystallography, X-Ray / Cyclic GMP - analogs & derivatives / Cyclic GMP - metabolism / Developmental Biology / Dimerization / Human Genetics / L-Trp / L-色氨酸 / Life Sciences / Molecular Dynamics Simulation / Molecular Sequence Data / Mutagenesis / peptidoglycan layer / Protein Science / Protein Structure, Quaternary / Pseudomonas aeruginosa / Pseudomonas aeruginosa - metabolism / Research Article / Sequence Alignment / Stem Cells / the YfiBNR system / Tryptophan - chemistry / Tryptophan - metabolism / Vitamin B 6 - chemistry / Vitamin B 6 - metabolism / Vitamin B6 / 信号系统 / 化学计量学 / 抗生素耐药性 / 晶体结构 / 监管机制 / 结构紧凑 / 铜绿假单胞菌