Structures of a non-ribosomal peptide synthetase condensation domain suggest the basis of substrate selectivity

Nat Commun. 2021 May 4;12(1):2511. doi: 10.1038/s41467-021-22623-0.


Non-ribosomal peptide synthetases are important enzymes for the assembly of complex peptide natural products. Within these multi-modular assembly lines, condensation domains perform the central function of chain assembly, typically by forming a peptide bond between two peptidyl carrier protein (PCP)-bound substrates. In this work, we report structural snapshots of a condensation domain in complex with an aminoacyl-PCP acceptor substrate. These structures allow the identification of a mechanism that controls access of acceptor substrates to the active site in condensation domains. The structures of this complex also allow us to demonstrate that condensation domain active sites do not contain a distinct pocket to select the side chain of the acceptor substrate during peptide assembly but that residues within the active site motif can instead serve to tune the selectivity of these central biosynthetic domains.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Amino Acids / chemistry*
  • Catalytic Domain*
  • Chromatography, High Pressure Liquid
  • Coenzyme A / chemistry
  • Crystallography, X-Ray
  • Gene Expression
  • Models, Molecular
  • Molecular Docking Simulation
  • Molecular Dynamics Simulation
  • Mutation
  • Peptide Synthases / chemistry*
  • Peptides / chemistry*
  • Protein Domains
  • Protein Structure, Tertiary
  • Sequence Alignment
  • Siderophores / biosynthesis
  • Siderophores / chemistry*
  • Substrate Specificity
  • Thermobifida / chemistry
  • Thermobifida / metabolism


  • Amino Acids
  • Peptides
  • Siderophores
  • Peptide Synthases
  • non-ribosomal peptide synthase
  • Coenzyme A

Supplementary concepts

  • Thermobifida fusca