TY - JOUR
T1 - Distinct Structural Elements Dictate the Specificity of the Type III Pentaketide Synthase from Neurospora crassa
AU - Rubin-Pitel, Sheryl B.
AU - Zhang, Houjin
AU - Vu, Trang
AU - Brunzelle, Joseph S.
AU - Zhao, Huimin
AU - Nair, Satish K.
N1 - Funding Information:
This research was supported by a grant from the Office of Naval Research (N00014-02-1-0725 to H.Z.) and NIGMS (S.K.N.). We thank John Chrzas and staff at SER-CAT (22-BM at Argonne National Laboratories) for facilitating data collection. We thank N. Nair for preparation of the Neurospora crassa mRNA library and Anuradha Biswas for assistance in protein purification. S.B.R.-P. acknowledges support from the National Institutes of Health Cell and Molecular Biology Training Grant Program and the National Science Foundation Graduate Research Fellowship Program. The Q-Tof Ultima mass spectrometer was purchased in part with a grant from the National Science Foundation, Division of Biological Infrastructure (DBI-0100085). The authors declare that they have no competing interests.
PY - 2008/10/20
Y1 - 2008/10/20
N2 - The fungal type III polyketide synthase 2′-oxoalkylresorcylic acid synthase (ORAS) primes with a range of acyl-Coenzyme A thioesters (C4-C20) and extends using malonyl-Coenzyme A to produce pyrones, resorcinols, and resorcylic acids. To gain insight into this unusual substrate specificity and product profile, we have determined the crystal structures of ORAS to 1.75 Å resolution, the Phe-252→Gly site-directed mutant to 2.1 Å resolution, and a binary complex of ORAS with eicosanoic acid to 2.0 Å resolution. The structures reveal a distinct rearrangement of structural elements near the active site that allows accommodation of long-chain fatty acid esters and a reorientation of the gating mechanism that controls cyclization and polyketide chain length. The roles of these structural elements are further elucidated by characterization of various structure-based site-directed variants. These studies establish an unexpected plasticity to the PKS fold, unanticipated from structural studies of other members of this enzyme family.
AB - The fungal type III polyketide synthase 2′-oxoalkylresorcylic acid synthase (ORAS) primes with a range of acyl-Coenzyme A thioesters (C4-C20) and extends using malonyl-Coenzyme A to produce pyrones, resorcinols, and resorcylic acids. To gain insight into this unusual substrate specificity and product profile, we have determined the crystal structures of ORAS to 1.75 Å resolution, the Phe-252→Gly site-directed mutant to 2.1 Å resolution, and a binary complex of ORAS with eicosanoic acid to 2.0 Å resolution. The structures reveal a distinct rearrangement of structural elements near the active site that allows accommodation of long-chain fatty acid esters and a reorientation of the gating mechanism that controls cyclization and polyketide chain length. The roles of these structural elements are further elucidated by characterization of various structure-based site-directed variants. These studies establish an unexpected plasticity to the PKS fold, unanticipated from structural studies of other members of this enzyme family.
KW - CHEMBIO
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U2 - 10.1016/j.chembiol.2008.08.011
DO - 10.1016/j.chembiol.2008.08.011
M3 - Article
C2 - 18940668
AN - SCOPUS:53649092534
SN - 1074-5521
VL - 15
SP - 1079
EP - 1090
JO - Chemistry and Biology
JF - Chemistry and Biology
IS - 10
ER -