Solution structure of the B. subtilis anti-sigma-F factor, FIN

Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

wwPDB Validation   3D Report Full Report

This is version 1.3 of the entry. See complete history


A novel RNA polymerase-binding protein that interacts with a sigma-factor docking site.

Wang Erickson, A.F.Deighan, P.Chen, S.Barrasso, K.Garcia, C.P.Martinez-Lumbreras, S.Alfano, C.Krysztofinska, E.M.Thapaliya, A.Camp, A.H.Isaacson, R.L.Hochschild, A.Losick, R.

(2017) Mol Microbiol 105: 652-662

  • DOI: https://doi.org/10.1111/mmi.13724
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Sporulation in Bacillus subtilis is governed by a cascade of alternative RNA polymerase sigma factors. We previously identified a small protein Fin that is produced under the control of the sporulation sigma factor σ F to create a negative feedback loop that inhibits σ F -directed gene transcription. Cells deleted for fin are defective for spore formation and exhibit increased levels of σ F -directed gene transcription. Based on pull-down experiments, chemical crosslinking, bacterial two-hybrid experiments and nuclear magnetic resonance chemical shift analysis, we now report that Fin binds to RNA polymerase and specifically to the coiled-coil region of the β' subunit. The coiled-coil is a docking site for sigma factors on RNA polymerase, and evidence is presented that the binding of Fin and σ F to RNA polymerase is mutually exclusive. We propose that Fin functions by a mechanism distinct from that of classic sigma factor antagonists (anti-σ factors), which bind directly to a target sigma factor to prevent its association with RNA polymerase, and instead functions to inhibit σ F by competing for binding to the β' coiled-coil.

  • Organizational Affiliation

    Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, 02115, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Anti-sigma-F factor Fin75Bacillus subtilisMutation(s): 0 
Gene Names: finsubAyabKBSU00540
Find proteins for P37553 (Bacillus subtilis (strain 168))
Explore P37553 
Go to UniProtKB:  P37553
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP37553
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on ZN

Download Ideal Coordinates CCD File 
B [auth A]ZINC ION
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2017-06-21
    Type: Initial release
  • Version 1.1: 2017-08-16
    Changes: Database references
  • Version 1.2: 2019-05-08
    Changes: Data collection
  • Version 1.3: 2023-06-14
    Changes: Data collection, Database references, Derived calculations, Other