期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2017
卷号：114
期号：29
页码：7497-7504
DOI：10.1073/pnas.1707385114
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：In Escherichia coli MinE induces MinC/MinD to oscillate between the ends of the cell, contributing to the precise placement of the Z ring at midcell. To do this, MinE undergoes a remarkable conformational change from a latent 6β-stranded form that diffuses in the cytoplasm to an active 4β-stranded form bound to the membrane and MinD. How this conformational switch occurs is not known. Here, using hydrogen–deuterium exchange coupled to mass spectrometry (HDX-MS) we rule out a model in which the two forms are in rapid equilibrium. Furthermore, HDX-MS revealed that a MinE mutant (D45A/V49A), previously shown to produce an aberrant oscillation and unable to assemble a MinE ring, is more rigid than WT MinE. This mutant has a defect in interaction with MinD, suggesting it has difficulty in switching to the active form. Analysis of intragenic suppressors of this mutant suggests it has difficulty in releasing the N-terminal membrane targeting sequences (MTS). These results indicate that the dynamic association of the MTS with the β-sheet is fine-tuned to balance MinE’s need to sense MinD on the membrane with its need to diffuse in the cytoplasm, both of which are necessary for the oscillation. The results lead to models for MinE activation and MinE ring formation.
