The structures of Listeria monocytogenes MenD in ThDP-bound and in-crystallo captured intermediate I-bound forms
Michelle Bailey, Fiona M. Given, Ngoc Anh Thu Ho, F. Grant Pearce, Timothy M. Allison and Jodie M. Johnston [1]
Molecular Tour
The ThDP-dependent enzyme MenD (2-succinyl-5-enolpyruvyl-6- hydroxy-3-cyclohexene-1-carboxylate ()) synthase is involved in bacterial menaquinone biosynthesis. Menaquinones (vitamin K2), a family of redox-active small lipophilic molecules, are important to many bacteria acting as vital electron carriers in electron transport and energy generation. Menaquinones have also been implicated in a range of other roles variously linked to environmental adaptation, virulence, persistence, biofilm formation and sporulation in different bacteria. Humans don’t make menaquinone (though they get it from their diet and use if for very different uses as a cofactor for enzymes involved in blood clotting and bone health). Thus, the bacterial enzymes that make menaquinone have become of interest as antimicrobial drug targets.
In additional studies we used our structural analysis combined with other methods (size-exclusion chromatography, mass photometry and small angle X-ray scattering analysis) to understand the oligomeric state of the enzyme. Showing that like other MenD’s, Listeria monocytogenes MenD has a homotetrameric quaternary structure. We also undertook enzyme kinetics to show the enzyme was active, and that there was weak inhibition of enzyme activity in the presence of 1,4- dihydroxy-2-naphthoic acid, a downstream metabolite in the menaquinone-biosynthesis pathway that has previously been shown to be a potent allosteric regulator of Mycobacterium tuberculosis MenD.
References
- ↑ doi: https://dx.doi.org/10.1107/S2053230X25006181
