PDBsum entry: 2aut

Hydrolase

PDB id: 2aut

Contents

Protein chains

208 a.a. *

Ligands

PO4

Metals

_MG ×4

_NA

Waters ×534

* Residue conservation analysis

PDB id:

2aut

Name:

Hydrolase

Title:

Crystal structure of lys154asn mutant of mature apha of s. Typhimurium

Structure:

Apha. Chain: a, b, c, d. Engineered: yes. Mutation: yes

Source:

Salmonella typhimurium. Organism_taxid: 602. Gene: apha. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.

Biol. unit:

Tetramer (from PQS)

Resolution:

2.25Å R-factor: 0.151 R-free: 0.197

Authors:

R.D.Makde,G.D.Gupta,V.Kumar

Key ref:

R.D.Makde et al. (2007). 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. PubMed id: 17570338 DOI: 10.1016/j.abb.2007.03.043

Date:

29-Aug-05 Release date: 05-Sep-06

Protein chains

Q540U1  (Q540U1_SALTY) -  Class B non-specific acid phosphatase

Seq: 237 a.a.

Struc: 208 a.a.*

* PDB and UniProt seqs differ at 2 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.3.1.3.2 - Acid phosphatase.
• Reaction: A phosphate monoester + H₂O = an alcohol + phosphate

phosphate monoester + H(2)O = alcohol + phosphate (Bound ligand (Het Group name = PO4) corresponds exactly)

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

 Gene Ontology (GO) functional annotation 

• Cellular component: periplasmic space (2 terms)
• Biochemical function: hydrolase activity (3 terms)

reference

DOI no: 10.1016/j.abb.2007.03.043

Arch Biochem Biophys 464:70-79 (2007)

PubMed id: 17570338

Structural and mutational analyses reveal the functional role of active-site Lys-154 and Asp-173 of Salmonella typhimurium AphA protein.

R.D.Makde, G.D.Gupta, S.K.Mahajan, V.Kumar.

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).