Characterising the function and structure of a unique trans- acyltransferase enzyme from a modular polyketide synthase Fraser Windsor, Yit Heng Chooi, Alice Vrielink, Marianne Costa University of Western Australia, Australia Among the assembly line-like bacterial modular polyketide synthases (PKSs), the subgroup trans -acyltransferase ( trans- AT) PKSs have unique features that make them attractive targets for engineering and the production of novel polyketides. Like all PKSs in this group, trans -AT PKSs build polyketides from small acyl units with the intermediate passed along the PKS as biosynthesis occurs. What defines trans- AT PKSs is that the malonyl unit-selecting acyltransferase (AT) domains are standalone proteins that act iteratively, selecting for many steps of biosynthesis. Trans -AT PKSs offer the potential for altering acyl unit selection throughout the entire PKS by the engineering of a single standalone protein, however this vision is hampered by the near universal selection of only malonyl-CoA by trans- AT domains. Towards a fuller picture of acyltransferase activity in trans- AT PKSs, we are pursuing the structural and functional characterisation of one of the few known examples of a non-malonyl accepting trans- AT domain, revealing an acyl unit promiscuous enzyme with a unique fold among acyltransferase enzymes acting within PKS assembly lines. We are further interested in understanding and later engineering this enzyme’s interactions.
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© The Author(s), 2022
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