Download MendeleyA conserved motif flags acyl carrier proteins for beta-branching in polyketide synthesis.
Haines, A.S., Dong, X., Song, Z., Farmer, R., Williams, C., Hothersall, J., Poskon, E., Wattana-Amorn, P., Stephens, E.R., Yamada, E., Gurney, R., Takebayashi, Y., Masschelein, J., Cox, R.J., Lavigne, R., Willis, C.L., Simpson, T.J., Crosby, J., Winn, P.J., Thomas, C.M., Crump, M.P.(2013) Nat Chem Biol 9: 685-692
- PubMed: 24056399
- DOI: https://doi.org/10.1038/nchembio.1342
- Primary Citation of Related Structures:
2L22 - PubMed Abstract:
Type I polyketide synthases often use programmed β-branching, via enzymes of a 'hydroxymethylglutaryl-CoA synthase (HCS) cassette', to incorporate various side chains at the second carbon from the terminal carboxylic acid of growing polyketide backbones. We identified a strong sequence motif in acyl carrier proteins (ACPs) where β-branching is known to occur. Substituting ACPs confirmed a correlation of ACP type with β-branching specificity. Although these ACPs often occur in tandem, NMR analysis of tandem β-branching ACPs indicated no ACP-ACP synergistic effects and revealed that the conserved sequence motif forms an internal core rather than an exposed patch. Modeling and mutagenesis identified ACP helix III as a probable anchor point of the ACP-HCS complex whose position is determined by the core. Mutating the core affects ACP functionality, whereas ACP-HCS interface substitutions modulate system specificity. Our method for predicting β-carbon branching expands the potential for engineering new polyketides and lays a basis for determining specificity rules.
Organizational Affiliation:
School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
