Fine Tuning of Antibiotic Activity by a Tailoring Hydroxylase in a Trans‐AT Polyketide Synthase Pathway. (13th March 2018)

• Record Type: Journal Article
• Authors: Mohammad, Hadi H.; Connolly, Jack A.; Song, Zhongshu; Hothersall, Joanne; Race, Paul R.; Willis, Christine L.; Simpson, Thomas J.; Winn, Peter J.; Thomas, Christopher M.
• Is Part Of: Chembiochem. Volume 19:Number 8(2018)
• Page Start: 836
• Page End: 841
• Publication Date: 2018-03-13
• Subjects: antibiotics -- hydroxylation -- mupirocin -- polyketides -- thiomarinol; Biochemistry -- Periodicals; Molecular biology -- Periodicals; Pharmaceutical chemistry -- Periodicals; 572
• DOI: 10.1002/cbic.201800036
• Languages: English
• ISSNs: 1439-4227

Abstract

Abstract: The addition or removal of hydroxy groups modulates the activity of many pharmacologically active biomolecules. It can be integral to the basic biosynthetic factory or result from associated tailoring steps. For the anti‐MRSA antibiotic mupirocin, removal of a C8‐hydroxy group late in the biosynthetic pathway gives the active pseudomonic acid A. An extra hydroxylation, at C4, occurs in the related but more potent antibiotic thiomarinol A. We report here in vivo and in vitro studies that show that the putative non‐haem‐iron(II)/α‐ketoglutaratedependent dioxygenase TmuB, from the thiomarinol cluster, 4‐hydroxylates various pseudomonic acids whereas C8‐OH, and other substituents around the tetrahydropyran ring, block enzyme action but not substrate binding. Molecular modelling suggested a basis for selectivity, but mutation studies had a limited ability to rationally modify TmuB substrate specificity. 4‐Hydroxylation had opposite effects on the potency of mupirocin and thiomarinol. Thus, TmuB can be added to the toolbox of polyketide tailoring technologies for the in vivo generation of new antibiotics in the future. Abstract : As long as there's nothing on at 8 : TmuB has been identified as the enzyme responsible for 4‐hydroxylation of the antibiotic thiomarinol. Purified TmuB also efficiently 4‐hydroxylates pseudomonic acid A (PA‐A), the active ingredient of the related trans‐AT family antibiotic mupirocin, but can only weakly hydroxylate PA‐B, which has an 8‐OH.