Thioesterase domain TE is responsible for cyclizing

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Thioesterase domain (TE) is responsible for
cyclizing polyketide chain and release the
product
6-deoxyerthronolide B synthase (DEBS)
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Model substrates in this study
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Stereo-selectivity of TE domain
a estimated using two data points
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Substrates specificity of TE domain
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Kinetic study of TE catalyzed hydrolysis

• His 259 and Asp 169 are part of the catalytic
  triads, they are the negative controls in this
  study
• S80A and T261A are catalytically inactive because
  they have lost an important H-bond to Ala77 and
  Asp259 respectively
• Other mutation loss catalytic activity may due to
  the misfolding of the protein

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Result and Conclusion

• Most TE-mutants have low or no catalytic activity
• Mutants E184A Q264A showed comparable kinetic
  profiles to the wild-type TE
• H-bonding may not be critical for substrate
  recognition
• WT and mutations E184A , Q264A have high
  catalytic activity to simple substrates with
  amide bond

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Understanding substrate specificity of polyketide
synthase thioesterase domain Alanine scanning of
the substrate binding pocket Meng Wang and
Christopher N. Boddy Department of Chemistry
Syracuse University Syracuse, NY 13244