Crystallization and preliminary X-ray crystallographic analysis of biodegradative threonine deaminase (TdcB) from Salmonella typhimurium
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore (India)
- Department of Biochemistry, Indian Institute of Science, Bangalore (India)
S. typhimurium biodegradative threonine deaminase (TdcB), a member of the β-family of PLP-dependent enzymes, has been overexpressed, purified and crystallized in three different crystal forms using the hanging-drop vapour-diffusion method. Biodegradative threonine deaminase (TdcB) catalyzes the deamination of l-threonine to α-ketobutyrate, the first reaction in the anaerobic breakdown of l-threonine to propionate. Unlike the biosynthetic threonine deaminase, TdcB is insensitive to l-isoleucine and is activated by AMP. Here, the cloning of TdcB (molecular weight 36 kDa) from Salmonella typhimurium with an N-terminal hexahistidine affinity tag and its overexpression in Escherichia coli is reported. TdcB was purified to homogeneity using Ni–NTA affinity column chromatography and crystallized using the hanging-drop vapour-diffusion technique in three different crystal forms. Crystal forms I (unit-cell parameters a = 46.32, b = 55.30, c = 67.24 Å, α = 103.09, β = 94.70, γ = 112.94°) and II (a = 56.68, b = 76.83, c = 78.50 Å, α = 66.12, β = 89.16, γ = 77.08°) belong to space group P1 and contain two and four molecules of TdcB, respectively, in the asymmetric unit. Poorly diffracting form III crystals were obtained in space group C2 and based on the unit-cell volume are most likely to contain one molecule per asymmetric unit. Two complete data sets of resolutions 2.2 Å (crystal form I) and 1.7 Å (crystal form II) were collected at 100 K using an in-house X-ray source.
- OSTI ID:
- 22356286
- Journal Information:
- Acta Crystallographica. Section F, Vol. 62, Issue Pt 3; Other Information: PMCID: PMC2197173; PMID: 16511321; PUBLISHER-ID: en5156; OAI: oai:pubmedcentral.nih.gov:2197173; Copyright (c) International Union of Crystallography 2006; Country of input: International Atomic Energy Agency (IAEA); ISSN 1744-3091
- Country of Publication:
- United Kingdom
- Language:
- English
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