9XZN | pdb_00009xzn

Teichoic acid flippase TacF from Streptococcus pneumoniae


Experimental Data Snapshot

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.63 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 

wwPDB Validation 3D Report Full Report

Validation slider image for 9XZN

This is version 1.1 of the entry. See complete history

Literature

Mechanistic basis of teichoic acid transport by a gatekeeper flippase.

Cebrero, G.Chidananda, A.H.Cester, E.Denereaz, J.Demir, E.S.Mathew, A.T.Bhowmik, D.R.de Capitani, M.Reymond, J.L.Kannan, N.Avci, F.Y.Veening, J.W.Mehdipour, A.R.Perez, C.

(2026) bioRxiv 

  • DOI: https://doi.org/10.64898/2026.02.22.707263
  • Primary Citation Related Structures: 
    9XZN

  • PubMed Abstract: 

    The cell wall is a complex structure that protects bacteria from environmental threats. Phosphocholine-containing teichoic acids are key cell wall biopolymers critical for host colonization, immune evasion, competence, and persistence in Streptococcus pneumoniae . The flippase TacF, a member of the multidrug/oligosaccharide-lipid/polysaccharide (MOP) superfamily, monitors the phosphocholine content of teichoic acids during transport, yet the underlying mechanism of this process remains unknown. We present a cryo-EM structure of S. pneumoniae TacF in lipid nanodiscs. In vivo complementation assays and molecular dynamics simulations reveal key residues involved in teichoic acid recognition and transport, while coevolutionary and conservation analyses delineate common mechanistic elements among MOP flippases, indicating a shared mechanism for polyprenyl-diphosphate-linked oligosaccharide lipid transport. Our findings provide mechanistic insights into an essential flippase involved in S. pneumoniae pathogenesis and a potential drug target.

Macromolecule Content 

  • Total Structure Weight: 67.58 kDa 
  • Atom Count: 4,668 
  • Modeled Residue Count: 580 
  • Deposited Residue Count: 594 
  • Unique protein chains: 1

Macromolecules

Find similar proteins by:|  3D Structure
Entity ID: 1
MoleculeChains  Sequence LengthOrganismDetailsImage
Soluble cytochrome b562,Teichoic acid subunit flippaseA [auth B]594Escherichia coliStreptococcus pneumoniae R6
This entity is chimeric
Mutation(s): 0 
Gene Names: cybCspr1150
UniProt
Find proteins for P0ABE7 (Escherichia coli)
Explore P0ABE7 
Go to UniProtKB:  P0ABE7
Find proteins for Q8DPI1 (Streptococcus pneumoniae (strain ATCC BAA-255 / R6))
Explore Q8DPI1 
Go to UniProtKB:  Q8DPI1
Entity Groups
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupsP0ABE7Q8DPI1
Sequence Annotations
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Reference Sequence

Experimental Data & Validation

Experimental Data

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.63 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 
EM Software:
TaskSoftware PackageVersion
MODEL REFINEMENTPHENIX1.21.2_5419
RECONSTRUCTIONcryoSPARCv4.7.1

Structure Validation

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Entry History 

& Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Swiss National Science FoundationSwitzerland310030_207974
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United StatesR35GM158187

Revision History  (Full details and data files)

  • Version 1.0: 2026-04-29
    Type: Initial release
  • Version 1.1: 2026-05-20
    Changes: Data collection, Database references