2AUT

Crystal structure of Lys154Asn mutant of mature AphA of S. typhimurium

Summary for 2AUT

• Entry DOI: 10.2210/pdb2aut/pdb
• Related: 1Z5G 1Z5U 1Z88
• Descriptor: AphA, MAGNESIUM ION, SODIUM ION, ... (5 entities in total)
• Functional Keywords: class-b bacterial non-specific acid phosphatase, lys154asn mutant of mature apha, metalloenzyme, hydrolase
• Biological source: Salmonella typhimurium
• Cellular location: Periplasm : P58683
• Total number of polymer chains: 4
• Total formula weight: 95637.68

Authors

Makde, R.D.,Gupta, G.D.,Kumar, V. (deposition date: 2005-08-29, release date: 2006-09-05, Last modification date: 2023-08-23)

Primary citation

Makde, R.D.,Gupta, G.D.,Mahajan, S.K.,Kumar, V.
Structural and mutational analyses reveal the functional role of active-site Lys-154 and Asp-173 of Salmonella typhimurium AphA protein.
Arch.Biochem.Biophys., 464:70-79, 2007

PubMed Abstract: The Salmonella typhimurium class B nonspecific acid phosphatase (AphA protein) belongs to the L2-haloacid dehalogenase superfamily. The conserved Lys-154 interacts with substrate phosphate, nucleophile Asp-46, and Asp-173 in the wild-type AphA protein. Asp-173 also interacts with Mg(II) water ligand and with main-chain amide of loop-4. We report here the mutational analysis of Lys-154 and Asp-173, the crystal structures of the K154N and K154R mutants, and the results of electrostatic potential calculations. The K154N, K154R and D173N mutants display significant reduction in the phosphatase activity. Lys-154 may not be responsible for a juxtaposition of the substrate phosphate and the aspartyl nucleophile, but has an hitherto unknown functional role of rendering the substrate phosphorous atom electron deficient. Nearly 10,000-fold increase in the K(d) value for dissociation of the cofactor Mg(II) observed for the D173N mutant correlates well with theoretically estimated change in the binding free energy of Mg(II).

PubMed: 17570338
DOI: 10.1016/j.abb.2007.03.043

Experimental method

X-RAY DIFFRACTION (2.25 Å)