Reprogramming a module of the 6-deoxyerythronolide B synthase for iterative chain elongation

Proc Natl Acad Sci U S A. 2012 Mar 13;109(11):4110-5. doi: 10.1073/pnas.1118734109. Epub 2012 Feb 27.


Multimodular polyketide synthases (PKSs) have an assembly line architecture in which a set of protein domains, known as a module, participates in one round of polyketide chain elongation and associated chemical modifications, after which the growing chain is translocated to the next PKS module. The ability to rationally reprogram these assembly lines to enable efficient synthesis of new polyketide antibiotics has been a long-standing goal in natural products biosynthesis. We have identified a ratchet mechanism that can explain the observed unidirectional translocation of the growing polyketide chain along the 6-deoxyerythronolide B synthase. As a test of this model, module 3 of the 6-deoxyerythronolide B synthase has been reengineered to catalyze two successive rounds of chain elongation. Our results suggest that high selectivity has been evolutionarily programmed at three types of protein-protein interfaces that are present repetitively along naturally occurring PKS assembly lines.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Acyl Carrier Protein / metabolism
  • Amino Acid Sequence
  • Biocatalysis
  • Models, Molecular
  • Molecular Sequence Data
  • Polyketide Synthases / chemistry*
  • Polyketide Synthases / metabolism*
  • Polyketides / chemistry
  • Polyketides / metabolism*
  • Protein Engineering
  • Protein Transport
  • Substrate Specificity


  • Acyl Carrier Protein
  • Polyketides
  • Polyketide Synthases