4QYR:
reference: Structural and evolutionary relationships of "AT-less" type I polyketide synthase ketosynthases., Lohman JR, Ma M, Osipiuk J, Nocek B, Kim Y, Chang C, Cuff M, Mack J, Bigelow L, Li H, Endres M, Babnigg G, Joachimiak A, Phillips GN Jr, Shen B, Proc Natl Acad Sci U S A. 2015 Oct 13;112(41):12693-8. doi:, 10.1073/pnas.1515460112. Epub 2015 Sep 29. PMID: 26420866

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