PDBsum entry 4ikc

Hydrolase

PDB id: 4ikc

Contents

Protein chain

274 a.a.

Ligands

SO4

Metals

_CL

Waters ×284

PDB id:

4ikc

Name:

Hydrolase

Title:

Crystal structure of catalytic domain of ptprq

Structure:

Phosphotidylinositol phosphatase ptprq. Chain: a. Fragment: unp residues 2015-2254. Synonym: receptor-type tyrosine-protein phosphatase q, ptp-rq, r-ptp- q. Engineered: yes. Mutation: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: ptprq. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

1.56Å R-factor: 0.148 R-free: 0.165

Authors:

K.R.Yu,S.E.Ryu,S.J.Kim

Key ref:

K.R.Yu et al. (2013). Structural basis for the dephosphorylating activity of PTPRQ towards phosphatidylinositide substrates. Acta Crystallogr D Biol Crystallogr, 69, 1522-1529. PubMed id: 23897475 DOI: 10.1107/S0907444913010457

Date:

26-Dec-12 Release date: 31-Jul-13

Protein chain

Q9UMZ3  (PTPRQ_HUMAN) -  Phosphatidylinositol phosphatase PTPRQ from Homo sapiens

Seq: 2332 a.a.

Struc: 274 a.a.*

* PDB and UniProt seqs differ at 3 residue positions (black crosses)

Enzyme reactions

• Enzyme class 1: E.C.3.1.3.67 - phosphatidylinositol-3,4,5-trisphosphate 3-phosphatase.
• Pathway: 1-Phosphatidyl-myo-inositol Metabolism
• Reaction: a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol-3,4,5-trisphosphate) + H2O = a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol-4,5- bisphosphate) + phosphate
• Cofactor: Mg(2+)
• Enzyme class 2: E.C.3.1.3.86 - phosphatidylinositol-3,4,5-trisphosphate 5-phosphatase.
• Reaction: a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol-3,4,5-trisphosphate) + H2O = a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol-3,4- bisphosphate) + phosphate
• Enzyme class 3: E.C.3.1.3.95 - phosphatidylinositol-3,5-bisphosphate 3-phosphatase.
• Reaction: a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol-3,5-bisphosphate) + H2O = a 1,2-diacyl-sn-glycero-3-phospho-(1D-myo-inositol-5-phosphate) + phosphate

Note, where more than one E.C. class is given (as above), each may correspond to a different protein domain or, in the case of polyprotein precursors, to a different mature protein.

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

reference

DOI no: 10.1107/S0907444913010457

Acta Crystallogr D Biol Crystallogr 69:1522-1529 (2013)

PubMed id: 23897475

Structural basis for the dephosphorylating activity of PTPRQ towards phosphatidylinositide substrates.

K.R.Yu, Y.J.Kim, S.K.Jung, B.Ku, H.Park, S.Y.Cho, H.Jung, S.J.Chung, K.H.Bae, S.C.Lee, B.Y.Kim, R.L.Erikson, S.E.Ryu, S.J.Kim.

ABSTRACT

Unlike other classical protein tyrosine phosphatases (PTPs), PTPRQ (PTP receptor type Q) has dephosphorylating activity towards phosphatidylinositide (PI) substrates. Here, the structure of the catalytic domain of PTPRQ was solved at 1.56 Å resolution. Overall, PTPRQ adopts a tertiary fold typical of other classical PTPs. However, the disordered M6 loop of PTPRQ surrounding the catalytic core and the concomitant absence of interactions of this loop with residues in the PTP loop results in a flat active-site pocket. On the basis of structural and biochemical analyses, it is proposed that this structural feature might facilitate the accommodation of large substrates, making it suitable for the dephosphorylation of PI substrates. Moreover, subsequent kinetic experiments showed that PTPRQ has a strong preferences for PI(3,4,5)P3 over other PI substrates, suggesting that its regulation of cell survival and proliferation reflects downregulation of Akt signalling.