The FtsLB subcomplex of the bacterial divisome is a tetramer with an uninterrupted FtsL helix linking the transmembrane and periplasmic regions
| Autor: | Alessandro Senes, Janice L. Robertson, Rahul Chadda, John A. Crooks, Loren M. LaPointe, Deena Al Mahbuba, Ambalika S. Khadria, Samson G.F. Condon, Aaron A. Hoskins, Gladys Diaz-Vazquez, Douglas B. Weibel, Samuel J. Craven, Qiang Cui, Claire R. Armstrong, Nambirajan Rangarajan |
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| Rok vydání: | 2018 |
| Předmět: |
Models
Molecular 0301 basic medicine Protein subunit 030106 microbiology Cell Cycle Proteins Microbiology Biochemistry Protein Structure Secondary 03 medical and health sciences chemistry.chemical_compound Tetramer Escherichia coli Molecular Biology Coiled coil Escherichia coli Proteins Cell Membrane Membrane Proteins Cell Biology Periplasmic space Transmembrane protein 030104 developmental biology Förster resonance energy transfer chemistry Multiprotein Complexes Periplasm Helix Biophysics Peptidoglycan |
| Zdroj: | Journal of Biological Chemistry. 293:1623-1641 |
| ISSN: | 0021-9258 |
| Popis: | In Escherichia coli, FtsLB plays a central role in the initiation of cell division, possibly transducing a signal that will eventually lead to the activation of peptidoglycan remodeling at the forming septum. The molecular mechanisms by which FtsLB operates in the divisome, however, are not understood. Here, we present a structural analysis of the FtsLB complex, performed with biophysical, computational, and in vivo methods, that establishes the organization of the transmembrane region and proximal coiled coil of the complex. FRET analysis in vitro is consistent with formation of a tetramer composed of two FtsL and two FtsB subunits. We predicted subunit contacts through co-evolutionary analysis and used them to compute a structural model of the complex. The transmembrane region of FtsLB is stabilized by hydrophobic packing and by a complex network of hydrogen bonds. The coiled coil domain probably terminates near the critical constriction control domain, which might correspond to a structural transition. The presence of strongly polar amino acids within the core of the tetrameric coiled coil suggests that the coil may split into two independent FtsQ-binding domains. The helix of FtsB is interrupted between the transmembrane and coiled coil regions by a flexible Gly-rich linker. Conversely, the data suggest that FtsL forms an uninterrupted helix across the two regions and that the integrity of this helix is indispensable for the function of the complex. The FtsL helix is thus a candidate for acting as a potential mechanical connection to communicate conformational changes between periplasmic, membrane, and cytoplasmic regions. |
| Databáze: | OpenAIRE |
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