NMR structure of TPC3 in TFE

Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 22 
  • Selection Criteria: non-violating structures 

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This is version 1.3 of the entry. See complete history


Structure-Activity Analysis of Quorum-Sensing Signaling Peptides from Streptococcus mutans.

Syvitski, R.T.Tian, X.L.Sampara, K.Salman, A.Lee, S.F.Jakeman, D.L.Li, Y.H.

(2007) J Bacteriol 189: 1441-1450

  • DOI: https://doi.org/10.1128/JB.00832-06
  • Primary Citation of Related Structures:  
    2I2H, 2I2J

  • PubMed Abstract: 

    Streptococcus mutans secretes and utilizes a 21-amino-acid signaling peptide pheromone to initiate quorum sensing for genetic competence, biofilm formation, stress responses, and bacteriocin production. In this study, we designed and synthesized a series of truncated peptides and peptides with amino acid substitutions to investigate their structure-activity relationships based on the three-dimensional structures of S. mutans wild-type signaling peptide UA159sp and C-terminally truncated peptide TPC3 from mutant JH1005 defective in genetic competence. By analyzing these peptides, we demonstrated that the signaling peptide of S. mutans has at least two functional domains. The C-terminal structural motif consisting of a sequence of polar hydrophobic charged residues is crucial for activation of the signal transduction pathway, while the core alpha-helical structure extending from residue 5 to the end of the peptide is required for receptor binding. Peptides in which three or more residues were deleted from the C terminus did not induce genetic competence but competitively inhibited quorum sensing activated by UA159sp. Disruption of the amphipathic alpha-helix by replacing the Phe-7, Phe-11, or Phe-15 residue with a hydrophilic residue resulted in a significant reduction in or complete loss of the activity of the peptide. In contrast to the C-terminally truncated peptides, these peptides with amino acid substitutions did not compete with UA159sp to activate quorum sensing, suggesting that disruption of the hydrophobic face of the alpha-helical structure results in a peptide that is not able to bind to the receptor. This study is the first study to recognize the importance of the signaling peptide C-terminal residues in streptococcal quorum sensing.

  • Organizational Affiliation

    College of Pharmacy, Dalhousie University, Halifax, Nova Scotia, Canada.


Find similar proteins by:  Sequence   |   3D Structure  

Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
signaling peptide TCP319N/AMutation(s): 0 
Find proteins for Q9APK6 (Streptococcus mutans)
Explore Q9APK6 
Go to UniProtKB:  Q9APK6
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Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9APK6
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 22 
  • Selection Criteria: non-violating structures 

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-10-17
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2022-03-09
    Changes: Data collection, Database references, Derived calculations