PDBsum entry: 1p8a

Hydrolase

PDB id: 1p8a

Contents

Protein chain

146 a.a. *

* Residue conservation analysis

PDB id:

1p8a

Name:

Hydrolase

Title:

Solution structure of the low molecular weight protein tyrosine phosphatase from tritrichomonas foetus

Structure:

Protein tyrosine phosphatase. Chain: a. Engineered: yes. Mutation: yes

Source:

Tritrichomonas foetus. Organism_taxid: 5724. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.

NMR struc:

21 models

Authors:

C.L.Gustafson,C.V.Stauffacher,K.Hallenga,R.L.Van Etten

Key ref:

C.L.Gustafson et al. (2005). Solution structure of the low-molecular-weight protein tyrosine phosphatase from Tritrichomonas foetus reveals a flexible phosphate binding loop. Protein Sci, 14, 2515-2525. PubMed id: 16195543 DOI: 10.1110/ps.051618805

Date:

06-May-03 Release date: 15-Jun-04

Protein chain

O00810  (O00810_TRIFO) -  Protein tyrosine phosphatase

Seq: 147 a.a.

Struc: 146 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

 Gene Ontology (GO) functional annotation 

• Biological process: protein amino acid dephosphorylation (1 term)
• Biochemical function: protein tyrosine phosphatase activity (1 term)

DOI no: 10.1110/ps.051618805

Protein Sci 14:2515-2525 (2005)

PubMed id: 16195543

Solution structure of the low-molecular-weight protein tyrosine phosphatase from Tritrichomonas foetus reveals a flexible phosphate binding loop.

C.L.Gustafson, C.V.Stauffacher, K.Hallenga, R.L.Van Etten.

ABSTRACT

Eukaryotic low-molecular-weight protein tyrosine phosphatases (LMW PTPs) contain a conserved serine, a histidine with an elevated pKa, and an active site asparagine that together form a highly conserved hydrogen bonding network. This network stabilizes the active site phosphate binding loop for optimal substrate binding and catalysis. In the phosphatase from the bovine parasite Tritrichomonas foetus (TPTP), both the conserved serine (S37) and asparagine (N14) are present, but the conserved histidine has been replaced by a glutamine residue (Q67). Site-directed mutagenesis, kinetic, and spectroscopic experiments suggest that Q67 is located near the active site and is important for optimal catalytic activity. Kinetic experiments also suggest that S37 participates in the active site/hydrogen bonding network. Nuclear magnetic resonance spectroscopy was used to determine the three-dimensional structure of the TPTP enzyme and to further examine the roles of S37 and Q67. The backbone conformation of the TPTP phosphate binding loop is nearly superimposable with that of other tyrosine phosphatases, with N14 existing in a strained, left-handed conformation that is a hallmark of the active site hydrogen bonding network in the LMW PTPs. As expected, both S37 and Q67 are located at the active site, but in the consensus structure they are not within hydrogen bonding distance of N14. The hydrogen bond interactions that are observed in X-ray structures of LMW PTPs may in fact be transient in solution. Protein dynamics within the active site hydrogen bonding network appear to be affected by the presence of substrate or bound inhibitors such as inorganic phosphate.

Selected figure(s)

Figure 2.
Figure 2. Solution structure of wild-type TPTP. (A) Superposition of the C^ traces showing the overall precision of the 20 lowest energy structures (MOLMOL [Koradi et al. 1996]). (B) Ribbon diagram of the energy minimized average wild-type TPTP structure (MOLSCRIPT [Kraulis 1991]; Raster3D [Merritt and Bacon 1997]). The P-loop is shown in red.

Figure 5.
Figure 5. Stereo view comparison of critical residues in the active site hydrogen bonding network of LMW PTPs. From top to bottom, the structures are BPTP NMR (PDB file 1BVH [PDB] ), BPTP X-ray, (PDB file 1PNT [PDB] ), wild-type TPTP, and Q67-N14 TPTP. Hydrogen atoms are omitted for clarity (MOLSCRIPT [Kraulis 1991]; Raster 3D [Merritt and Bacon 1997]). All distances are in angstroms.

The above figures are reprinted by permission from the Protein Society: Protein Sci (2005, 14, 2515-2525) copyright 2005.

Figures were selected by an automated process.