Pyoluteorin is an antifungal agent composed of a 4,5-dichlorinated pyrrole group linked to a resorcinol moiety. The pyoluteorin biosynthetic gene cluster in Pseudomonas fluorescens Pf-5 encodes the halogenase PltA, which has been previously demonstrated to perform both chlorinations in vitro. PltA selectively accepts as a substrate a pyrrole moiety covalently tethered to a nonribosomal peptide thiolation domain PltL (pyrrolyl- S-PltL) for FAD-dependent di-chlorination, yielding 4,5-dichloropyrrolyl- S-PltL. We report a 2.75 Å-resolution crystal structure of PltA in complex with FAD and chloride. PltA is a dimeric enzyme, containing a flavin-binding fold conserved in flavin-dependent halogenases and monooxygenases, and an additional unique helical region at the C-terminus. This C-terminal region blocks a putative substrate-binding cleft, suggesting that a conformational change involving repositioning of this region is necessary to allow binding of the pyrrolyl- S-PltL substrate for its dichlorination by PltA.
|Number of pages||9|
|Journal||Journal of Structural Biology|
|State||Published - Dec 2015|
Bibliographical noteFunding Information:
This work was supported by an NSF Career Award MCB-1149427 (to S.G.-T.), a Grant (to O.V.T.) as part of the National Center for Advancing Translational Sciences ( UL1TR000117 ), and startup funds from the College of Pharmacy at the University of Kentucky (to S.G.-T. and O.V.T.). We thank the staff of sector 22 (SER-CAT) of the Advanced Photon Source at the Argonne National Laboratories for their assistance with the remote X-ray diffraction data collection.
© 2015 Elsevier Inc.
- Natural product
ASJC Scopus subject areas
- Structural Biology