Targeting the Unique Mechanism of Bacterial 1-Deoxy- d -xylulose-5-phosphate Synthase

David Bartee, Caren L. Freel Meyers

Research output: Contribution to journalArticlepeer-review

Abstract

The bacterial metabolite 1-deoxy-d-xyulose 5-phosphate (DXP) is essential in bacterial central metabolism feeding into isoprenoid, thiamin diphosphate (ThDP), and pyridoxal phosphate de novo biosynthesis. Halting its production through the inhibition of DXP synthase is an attractive strategy for the development of novel antibiotics. Recent work has revealed that DXP synthase utilizes a unique random sequential mechanism that requires formation of a ternary complex among pyruvate-derived C2α-lactylthiamin diphosphate (LThDP), d-glyceraldehyde 3-phosphate (d-GAP), and enzyme, setting it apart from all other known ThDP-dependent enzymes. Herein, we describe the development of bisubstrate inhibitors bearing an acetylphosphonate (AP) pyruvate mimic and a distal negative charge mimicking the phosphoryl group of d-GAP, designed to target the unique form of DXP synthase that binds LThDP and d-GAP in a ternary complex. A d-phenylalanine-derived triazole acetylphosphonate (d-PheTrAP) emerged as the most potent inhibitor in this series, displaying slow, tight-binding inhibition with a K i ∗ of 90 ± 10 nM, forward (k 1 ) and reverse (k 2 ) isomerization rates of 1.1 and 0.14 min -1 , respectively, and exquisite selectivity (>15000-fold) for DXP synthase over mammalian pyruvate dehydrogenase. d-PheTrAP is the most potent, selective DXP synthase inhibitor described to date and represents the first inhibitor class designed specifically to exploit the unique E-LThDP-GAP ternary complex in ThDP enzymology.

Original languageEnglish (US)
Pages (from-to)4349-4356
Number of pages8
JournalBiochemistry
Volume57
Issue number29
DOIs
StatePublished - Jul 24 2018

ASJC Scopus subject areas

  • Biochemistry

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