Structural analysis of N-acetylglucosamine-6-phosphate deacetylase apoenzyme from Escherichia coli.Ferreira, F.M., Mendoza-Hernandez, G., Aparicio, R., Fischer, H., Calcagno, M.L., Oliva, G.
(2006) J.Mol.Biol. 359: 308-321
- PubMed: 16630633
- DOI: 10.1016/j.jmb.2006.03.024
- PubMed Abstract:
- Crystallization and preliminary crystallographic analysis of N-acetylglucosamine 6-phosphate deacetylase from Escherichia coli
Ferreira, F.M.,Mendoza-Hernandez, G.,Calcagno, M.L.,Minauro, F.,Delboni, L.F.,Oliva, G.
(2000) Acta Crystallogr.,Sect.D 56: 670
We report the crystal structure of the apoenzyme of N-acetylglucosamine-6-phosphate (GlcNAc6P) deacetylase from Escherichia coli (EcNAGPase) and the spectrometric evidence of the presence of Zn2+ in the native protein. The GlcNAc6P deacetylase is an ...
We report the crystal structure of the apoenzyme of N-acetylglucosamine-6-phosphate (GlcNAc6P) deacetylase from Escherichia coli (EcNAGPase) and the spectrometric evidence of the presence of Zn2+ in the native protein. The GlcNAc6P deacetylase is an enzyme of the amino sugar catabolic pathway that catalyzes the conversion of the GlcNAc6P into glucosamine 6-phosphate (GlcN6P). The crystal structure was phased by the single isomorphous replacement with anomalous scattering (SIRAS) method using low-resolution (2.9 A) iodine anomalous scattering and it was refined against a native dataset up to 2.0 A resolution. The structure is similar to two other NAGPases whose structures are known from Thermotoga maritima (TmNAGPase) and Bacillus subtilis (BsNAGPase); however, it shows a phosphate ion bound at the metal-binding site. Compared to these previous structures, the apoenzyme shows extensive conformational changes in two loops adjacent to the active site. The E. coli enzyme is a tetramer and its dimer-dimer interface was analyzed. The tetrameric structure was confirmed in solution by small-angle X-ray scattering data. Although no metal ions were detected in the present structure, experiments of photon-induced X-ray emission (PIXE) spectra and of inductively coupled plasma emission spectroscopy (ICP-AES) with enzyme that was neither exposed to chelating agents nor metal ions during purification, revealed the presence of 1.4 atoms of Zn per polypeptide chain. Enzyme inactivation by metal-sequestering agents and subsequent reactivation by the addition of several divalent cations, demonstrate the role of metal ions in EcNAGPase structure and catalysis.
Instituto de Física de São Carlos, Universidade de São Paulo, C.P. 369, 13560-970 São Carlos, SP, Brazil.