|Sieminska, E. A. L.; Macova, A.; Palmer, D. R. J.; Sanders, D. A. R.
Crystallization and preliminary X-ray analysis of
(SHCHC) synthase (MenD) from Escherichia coli. In: Acta Crystallogr. Sect. F Struct. Biol. Cryst. Commun.. 61 (Pt 5)
- Titel des ArtikelsCrystallization and preliminary X-ray analysis of
(SHCHC) synthase (MenD) from Escherichia coli
(SHCHC) synthase, also called MenD, participates in the menaquinone (vitamin K2) biosynthetic pathway. The enzyme is
a part of the superfamily of ThDP-dependent enzymes; however, it is the only enzyme known to catalyze a Stetter-like
1,4-addition of a ThDP adduct to the β-carbon of an unsaturated carboxylate. This is the first reported
crystallization of the apoenzyme and holoenzyme forms of MenD. The apoenzyme crystals were obtained by sitting-drop
vapour diffusion with 70% MPD. However, the crystals were too small to collect diffraction data and a search for
better conditions was not successful. Single crystals of the holoenzyme with ThDP and Mn2+
as cofactors were obtained by the hanging-drop vapour-diffusion method with 35% ethylene glycol as precipitant.
Diffraction data were collected on a cryocooled crystal to a resolution of 2.0 Å at BioCARS, Advanced Photon Source
(APS), Chicago, IL, USA. The crystal was found to belong to space group P212121, with unit-cell parameters a =
106.86, b = 143.06, c = 156.85 Å, α = β = γ = 90°.