Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 30 
  • Conformers Submitted: 10 
  • Selection Criteria: structures with the lowest energy 

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This is version 1.3 of the entry. See complete history


Solution structure of PAFP-S: a new knottin-type antifungal peptide from the seeds of Phytolacca americana

Gao, G.H.Liu, W.Dai, J.X.Wang, J.F.Hu, Z.Zhang, Y.Wang, D.C.

(2001) Biochemistry 40: 10973-10978

  • DOI: https://doi.org/10.1021/bi010167k
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The three-dimensional solution structure of PAFP-S, an antifungal peptide extracted from the seeds of Phytolacca americana, was determined using 1H NMR spectroscopy. This cationic peptide contains 38 amino acid residues. Its structure was determined from 302 distance restraints and 36 dihedral restraints derived from NOEs and coupling constants. The peptide has six cysteines involved in three disulfide bonds. The previously unassigned parings have now been determined from NMR data. The solution structure of PAFP-S is presented as a set of 20 structures using ab initio dynamic simulated annealing, with an average RMS deviation of 1.68 A for the backbone heavy atoms and 2.19 A for all heavy atoms, respectively. For the well-defined triple-stranded beta-sheet involving residues 8-10, 23-27, and 32-36, the corresponding values were 0.39 and 1.25 A. The global fold involves a cystine-knotted three-stranded antiparallel beta-sheet (residues 8-10, 23-27, 32-36), a flexible loop (residues 14-19), and four beta-reverse turns (residues 4-8, 11-14, 19-22, 28-32). This structure features all the characteristics of the knottin fold. It is the first structural model of an antifungal peptide that adopts a knottin-type structure. PAFP-S has an extended hydrophobic surface comprised of residues Tyr23, Phe25, Ile27, Tyr32, and Val34. The side chains of these residues are well-defined in the NMR structure. Several hydrophilic and positively charged residues (Arg9, Arg38, and Lys36) surround the hydrophobic surface, giving PAFP-S an amphiphilic character which would be the main structural basis of its biological function.

  • Organizational Affiliation

    Laboratory of Molecular Biophysics, National Laboratory of Macromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
ANTIFUNGAL PEPTIDE38Phytolacca americanaMutation(s): 0 
Membrane Entity: Yes 
Find proteins for P81418 (Phytolacca americana)
Explore P81418 
Go to UniProtKB:  P81418
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP81418
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 30 
  • Conformers Submitted: 10 
  • 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: 2000-12-13
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2022-02-16
    Changes: Data collection, Database references, Derived calculations