Download MendeleyThe Helix Rearrangement in the Periplasmic Domain of the Flagellar Stator B Subunit Activates Peptidoglycan Binding and Ion Influx.
Kojima, S., Takao, M., Almira, G., Kawahara, I., Sakuma, M., Homma, M., Kojima, C., Imada, K.(2018) Structure 26: 590-598.e5
- PubMed: 29576320
- DOI: https://doi.org/10.1016/j.str.2018.02.016
- Primary Citation of Related Structures:
5Y3Z, 5Y40 - PubMed Abstract:
The stator of the bacterial flagellar motor couples ion flow with torque generation. The ion-conducting stator channel opens only when incorporated into and anchored around the rotor via the peptidoglycan (PG) binding domain of the B subunit (MotB C ). However, no direct evidence of PG binding coupled with channel activation has been presented. Here, we report the structural rearrangements of MotB C responsible for this coupling process. A MotB C fragment with the L119P replacement, which is known to cause channel activation, was able to bind PG. Nuclear magnetic resonance analysis of MotB C and the crystal structure of the MotB C -L119P dimer revealed major structural changes in helix α1. In vivo crosslinking results confirm that a major rearrangement occurs. Our results suggest that, upon stator incorporation into the motor, helix α1 of MotB C changes into an extended non-helical structure. We propose that this change allows the stator both to bind PG and to open its proton channel.
Organizational Affiliation:
Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-Ku, Nagoya 464-8602, Japan. Electronic address: z47616a@cc.nagoya-u.ac.jp.
