Abstract

Article info Vol. 7  No. 3   pp.  67 ~ 70
Title Purification, Crystallization and X-ray crystallographic analysis of Homoserine O-succinyltransferase from Escherichia coli
Authors Hye-Young Sagong and Kyung-Jin Kim*
Institutions School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, KNU Institute for Microorganisms, Kyungpook National University, Daegu 41566, Korea *Correspondence: kkim@knu.ac.kr
Abstract Homoserine O-succinyltransferase from Escherichia coli (EcHST) is the first enzyme in methionine biosynthesis and it catalyzed the transfer of succinyl-group from succinyl-CoA to L-homoserine. EcHST has reported to be regulated by feedback inhibition and it controls the bacterial growth due to its instability. To improve the EcHST for industrial application, the protein was overexpressed and purified to homogeneity by Ni-NTA affinity and size-exclusion chromatography. The EcHST protein was crystallized using hanging-drop vapor-diffusion method in the presence of 25% polyethylene glycol 3350, 0.1 M HEPES, pH 7.5, and 0.1 M magnesium chloride at 295 K. X-ray diffraction data were collected to a maximum resolution of 1.7 Å. The EcHST crystals belonged to the space group P212121 with unit cell parameters a = 76.35 Å, b = 81.03 Å, c = 98.09, α = β = γ = 90.0°. With two molecules of EcHST per asymmetric unit, the crystal volume per unit of protein mass was 2.12 Å3 Da-1, which correspond to a solvent content was approximately 42.15%.