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- PDB-9fmz: Cryo-EM structure of the c-di-GMP-bound synthase:pEtN transferase... -
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Open data
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Basic information
Entry | Database: PDB / ID: 9fmz | ||||||
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Title | Cryo-EM structure of the c-di-GMP-bound synthase:pEtN transferase complex (BcsA-Bct-G3) from the E. coli cellulose secretion macrocomplex | ||||||
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![]() | MEMBRANE PROTEIN / Bacterial cellulose secretion | ||||||
Function / homology | Cellulose synthase, subunit B / Cellulose synthase BcsB, bacterial / Bacterial cellulose synthase subunit / cellulose biosynthetic process / UDP-alpha-D-glucose metabolic process / plasma membrane / Chem-C2E / Cyclic di-GMP-binding protein![]() | ||||||
Biological species | ![]() ![]() | ||||||
Method | ELECTRON MICROSCOPY / single particle reconstruction / cryo EM / Resolution: 3.6 Å | ||||||
![]() | Anso, I. / Krasteva, P.V. | ||||||
Funding support | European Union, 1items
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![]() | ![]() Title: Structural basis for synthase activation and cellulose modification in the E. coli Type II Bcs secretion system. Authors: Itxaso Anso / Samira Zouhir / Thibault Géry Sana / Petya Violinova Krasteva / ![]() ![]() Abstract: Bacterial cellulosic polymers constitute a prevalent class of biofilm matrix exopolysaccharides that are synthesized by several types of bacterial cellulose secretion (Bcs) systems, which include ...Bacterial cellulosic polymers constitute a prevalent class of biofilm matrix exopolysaccharides that are synthesized by several types of bacterial cellulose secretion (Bcs) systems, which include conserved cyclic diguanylate (c-di-GMP)-dependent cellulose synthase modules together with diverse accessory subunits. In E. coli, the biogenesis of phosphoethanolamine (pEtN)-modified cellulose relies on the BcsRQABEFG macrocomplex, encompassing inner-membrane and cytosolic subunits, and an outer membrane porin, BcsC. Here, we use cryogenic electron microscopy to shed light on the molecular mechanisms of BcsA-dependent recruitment and stabilization of a trimeric BcsG pEtN-transferase for polymer modification, and a dimeric BcsF-dependent recruitment of an otherwise cytosolic BcsERQ regulatory complex. We further demonstrate that BcsE, a secondary c-di-GMP sensor, can remain dinucleotide-bound and retain the essential-for-secretion BcsRQ partners onto the synthase even in the absence of direct c-di-GMP-synthase complexation, likely lowering the threshold for c-di-GMP-dependent synthase activation. Such activation-by-proxy mechanism could allow Bcs secretion system activity even in the absence of substantial intracellular c-di-GMP increase, and is reminiscent of other widespread synthase-dependent polysaccharide secretion systems where dinucleotide sensing and/or synthase stabilization are carried out by key co-polymerase subunits. | ||||||
History |
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Structure visualization
Structure viewer | Molecule: ![]() ![]() |
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Downloads & links
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Download
PDBx/mmCIF format | ![]() | 281.9 KB | Display | ![]() |
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PDB format | ![]() | 205.4 KB | Display | ![]() |
PDBx/mmJSON format | ![]() | Tree view | ![]() | |
Others | ![]() |
-Validation report
Arichive directory | ![]() ![]() | HTTPS FTP |
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-Related structure data
Related structure data | ![]() 50581MC ![]() 9fmtC ![]() 9fmvC ![]() 9fnnC ![]() 9fo7C ![]() 9fp0C ![]() 9fp2C C: citing same article ( M: map data used to model this data |
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Similar structure data | Similarity search - Function & homology ![]() |
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Links
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Assembly
Deposited unit | ![]()
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Components
#1: Protein | Mass: 59687.984 Da / Num. of mol.: 3 Source method: isolated from a genetically manipulated source Details: Purified Bcs macrocomplex with stoichiometry BcsA-BcsB6-BcsR2-BcsQ2-BcsE2-BcsF2-BcsG3 Source: (gene. exp.) ![]() ![]() ![]() ![]() #2: Protein | | Mass: 83345.844 Da / Num. of mol.: 1 Source method: isolated from a genetically manipulated source Source: (gene. exp.) ![]() ![]() Gene: bcsB, ACU57_05345, BK292_24560, E6D34_20685, EIZ93_09345, FJQ40_15525, GP975_08505, GQA06_10940, GQM04_12065, GRW57_12105, NEP60_23610 Production host: ![]() ![]() #3: Protein | | Mass: 104015.688 Da / Num. of mol.: 1 / Mutation: HA-FLAG tagged Source method: isolated from a genetically manipulated source Details: Purified Bcs macrocomplex with stoichiometry BcsA-BcsB6-BcsR2-BcsQ2-BcsE2-BcsF2-BcsG3 Source: (gene. exp.) ![]() ![]() ![]() ![]() #4: Chemical | Has ligand of interest | Y | Has protein modification | N | |
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-Experimental details
-Experiment
Experiment | Method: ELECTRON MICROSCOPY |
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EM experiment | Aggregation state: PARTICLE / 3D reconstruction method: single particle reconstruction |
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Sample preparation
Component | Name: Purified Bcs macrocomplex with stoichiometry BcsA-BcsB6-BcsR2-BcsQ2-BcsE2-BcsF2-BcsG3 Type: COMPLEX Details: Locally refined c-di-GMP-bound synthase:pEtN-transferase complex from the E. coli Bcs cellulose secretion macrocomplex Entity ID: #1-#3 / Source: RECOMBINANT |
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Molecular weight | Value: 0.99 MDa / Experimental value: NO |
Source (natural) | Organism: ![]() ![]() |
Source (recombinant) | Organism: ![]() ![]() |
Buffer solution | pH: 8 Details: 120 mM NaCL 20 mM HEPES pH8 5 mM MgCl2 10 uM ApppCp 4 uM c-di-GMP 0.01% LM-NPG |
Specimen | Conc.: 2 mg/ml / Embedding applied: NO / Shadowing applied: NO / Staining applied: NO / Vitrification applied: YES Details: Purification from solubilized membrane fraction using an anti-FLAG M2 affinity resin |
Specimen support | Grid material: GOLD / Grid mesh size: 300 divisions/in. / Grid type: UltrAuFoil R1.2/1.3 |
Vitrification | Instrument: FEI VITROBOT MARK IV / Cryogen name: ETHANE / Humidity: 100 % / Chamber temperature: 277 K |
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Electron microscopy imaging
Experimental equipment | ![]() Model: Titan Krios / Image courtesy: FEI Company |
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Microscopy | Model: FEI TITAN KRIOS |
Electron gun | Electron source: ![]() |
Electron lens | Mode: BRIGHT FIELD / Nominal defocus max: 2100 nm / Nominal defocus min: 300 nm / Cs: 2.7 mm |
Image recording | Electron dose: 49.35 e/Å2 / Film or detector model: GATAN K3 (6k x 4k) / Num. of grids imaged: 2 / Num. of real images: 20022 |
EM imaging optics | Energyfilter name: GIF Quantum LS / Energyfilter slit width: 20 eV |
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Processing
EM software |
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CTF correction | Type: PHASE FLIPPING AND AMPLITUDE CORRECTION | ||||||||||||||||||||||||
Particle selection | Num. of particles selected: 1359795 | ||||||||||||||||||||||||
Symmetry | Point symmetry: C1 (asymmetric) | ||||||||||||||||||||||||
3D reconstruction | Resolution: 3.6 Å / Resolution method: FSC 0.143 CUT-OFF / Num. of particles: 259200 / Num. of class averages: 1 / Symmetry type: POINT | ||||||||||||||||||||||||
Atomic model building | Space: REAL | ||||||||||||||||||||||||
Atomic model building | Details: ColabFold model of the E> coli BcsA-BcsG2 complex / Source name: Other / Type: in silico model |