2XT6: Crystal Structure Of Mycobacterium Smegmatis Alpha-Ketoglutarate Decarboxylase Homodimer (Orthorhombic Form)

The alpha-ketoglutarate dehydrogenase (KDH) complex is a major regulatory point of aerobic energy metabolism. Mycobacterium tuberculosis was reported to lack KDH activity, and the putative KDH E1o component, alpha-ketoglutarate decarboxylase (KGD), was instead assigned as a decarboxylase or carboligase. Here, we show that this protein does in fact sustain KDH activity, as well as the additional two reactions, and these multifunctional properties are shared by the Escherichia coli homolog, SucA. We also show that the mycobacterial enzyme is finely regulated by an additional acyltransferase-like domain and by the action of acetyl-CoA, a powerful allosteric activator able to enhance the concerted protein motions observed during catalysis. Our results uncover the functional plasticity of a crucial node in bacterial metabolism, which may be important for M. tuberculosis during host infection.
PDB ID: 2XT6Download
MMDB ID: 91690
PDB Deposition Date: 2010/10/5
Updated in MMDB: 2011/10
Experimental Method:
x-ray diffraction
Resolution: 2.74  Å
Source Organism:
Similar Structures:
Biological Unit for 2XT6: dimeric; determined by author and by software (PISA)
Molecular Components in 2XT6
Label Count Molecule
Proteins (2 molecules)
2-oxoglutarate Decarboxylase(Gene symbol: kgd)
Molecule annotation
Chemicals (6 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB