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Structure and function of a decarboxylating Agrobacterium tumefaciens keto-deoxy-d-galactarate dehydratase

DOI: 10.1021/bi501290k DOI Help
PMID: 25454257 PMID Help

Authors: Helena Taberman (University of Eastern Finland) , Martina Andberg (VTT Technical Research Centre of Finland) , Tarja Parkkinen (University of Eastern Finland) , Janne Jänis (University of Eastern Finland) , Merja Penttilä (VTT Technical Research Centre of Finland) , Nina Hakulinen (University of Eastern Finland) , Anu Koivula (VTT Technical Research Centre of Finland) , Juha Rouvinen (University of Eastern Finland)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Biochemistry , VOL 53 (51)

State: Published (Approved)
Published: December 2014

Abstract: Agrobacterium tumefaciens (At) strain C58 contains an oxidative enzyme pathway that can function on both d-glucuronic and d-galacturonic acid. The corresponding gene coding for At keto-deoxy-d-galactarate (KDG) dehydratase is located in the same gene cluster as those coding for uronate dehydrogenase (At Udh) and galactarolactone cycloisomerase (At Gci) which we have previously characterized. Here, we present the kinetic characterization and crystal structure of At KDG dehydratase, which catalyzes the next step, the decarboxylating hydrolyase reaction of KDG to produce alpha;-ketoglutaric semialdehyde (alpha;-KGSA) and carbon dioxide. The crystal structures of At KDG dehydratase and its complexes with pyruvate and 2-oxoadipic acid, two substrate analogues, were determined to 1.7 Å, 1.5 Å, and 2.1 Å resolution, respectively. Furthermore, mass spectrometry was used to confirm reaction end-products. The results lead us to propose a structure-based mechanism for At KDG dehydratase, suggesting that while the enzyme belongs to the Class I aldolase protein family, it does not follow a typical retro-aldol condensation mechanism.

Journal Keywords: Chemical structure; Crystal structure; Ligands; Monomers; Peptides and proteins

Diamond Keywords: Bacteria; Enzymes; Biofuel

Subject Areas: Biology and Bio-materials, Chemistry, Environment

Instruments: I03-Macromolecular Crystallography , I04-1-Macromolecular Crystallography (fixed wavelength)

Other Facilities: ESRF

Added On: 19/12/2014 19:40

Discipline Tags:

Bioenergy Earth Sciences & Environment Biotechnology Energy Climate Change Biochemistry Chemistry Structural biology Engineering & Technology Life Sciences & Biotech

Technical Tags:

Diffraction Macromolecular Crystallography (MX)