Crystal structure of a chimaeric bacterial glutamate dehydrogenase

Journal Article · Mon May 23 00:00:00 EDT 2016 · Acta Crystallographica. Section F, Structural Biology Communications

DOI:https://doi.org/10.1107/S2053230X16007305· OSTI ID:1314242

Oliveira, Tânia; Sharkey, Michael A.; Engel, Paul C.; Khan, Amir R.

Glutamate dehydrogenases (EC 1.4.1.2–4) catalyse the oxidative deamination of L-glutamate to α-ketoglutarate using NAD(P)⁺as a cofactor. The bacterial enzymes are hexameric, arranged with 32 symmetry, and each polypeptide consists of an N-terminal substrate-binding segment (domain I) followed by a C-terminal cofactor-binding segment (domain II). The catalytic reaction takes place in the cleft formed at the junction of the two domains. Distinct signature sequences in the nucleotide-binding domain have been linked to the binding of NAD⁺versusNADP⁺, but they are not unambiguous predictors of cofactor preference. In the absence of substrate, the two domains move apart as rigid bodies, as shown by the apo structure of glutamate dehydrogenase fromClostridium symbiosum. Here, the crystal structure of a chimaeric clostridial/Escherichia colienzyme has been determined in the apo state. The enzyme is fully functional and reveals possible determinants of interdomain flexibility at a hinge region following the pivot helix. The enzyme retains the preference for NADP⁺cofactor from the parentE. colidomain II, although there are subtle differences in catalytic activity.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
• Sponsoring Organization: FOREIGN
• OSTI ID: 1314242
• Journal Information: Acta Crystallographica. Section F, Structural Biology Communications, Vol. 72, Issue 6; ISSN 2053-230X
• Publisher: International Union of Crystallography
• Country of Publication: United States
• Language: ENGLISH