NMR solution structure of PisI

Experimental Data Snapshot

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

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Nuclear magnetic resonance solution structure of PisI, a group B immunity protein that provides protection against the type IIa bacteriocin piscicolin 126, PisA.

Martin-Visscher, L.A.Sprules, T.Gursky, L.J.Vederas, J.C.

(2008) Biochemistry 47: 6427-6436

  • DOI: https://doi.org/10.1021/bi8004076
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Lactic acid bacteria produce and secrete bacteriocins. These bacteriocins are potent antimicrobial peptides that are active against other closely related bacteria. As a means of self-protection, producer organisms also express immunity proteins. Immunity proteins are generally located on the same genetic locus and are cotranscribed with the bacteriocin. Although some cross immunity between bacteriocins has been observed, immunity proteins are typically highly specific. Immunity proteins for the type IIa bacteriocins range from 81 to 115 amino acids in length and display substantial variation in their sequences. Nonetheless, such immunity proteins have been classified into three groupings (groups A, B, and C) according to sequence homology. The structures of a group C (ImB2) and two group A (EntA-im and PedB) immunity proteins have previously been reported. We herein report the nuclear magnetic resonance solution structure of the remaining class of the type IIa immunity proteins. PisI, a 98-amino acid protein, is a group B immunity protein conferring immunity against piscicolin 126 (PisA). Like ImB2, EntA-im, and PedB, PisI folds into a globular protein in aqueous solution and contains an antiparallel four-helix bundle. Compared to ImB2 and EntA-im, PisI has a substantially longer and more flexible N-terminus, but a shorter C-terminus. No direct interaction between the bacteriocin and immunity protein is observed by NMR in either aqueous or membrane mimicking environments. This further suggests that the mechanism that mediates immunity is not due to a direct bacteriocin-immunity protein interaction but rather is receptor-mediated. It has now been confirmed that the four-helix bundle is indeed a structural motif among the type IIa immunity proteins.

  • Organizational Affiliation

    Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada T6G 2G2.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Putative piscicolin 126 immunity protein98Carnobacterium maltaromaticumMutation(s): 0 
Gene Names: pisI
Find proteins for Q2VU68 (Carnobacterium maltaromaticum)
Explore Q2VU68 
Go to UniProtKB:  Q2VU68
Entity Groups  
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UniProt GroupQ2VU68
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

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

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2008-06-17
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2020-02-19
    Changes: Data collection, Database references, Derived calculations, Other
  • Version 1.3: 2023-06-14
    Changes: Database references, Other
  • Version 1.4: 2024-05-08
    Changes: Data collection, Database references