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PDBsum entry 2c7s
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References listed in PDB file
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Key reference
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Title
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The crystal structure of human receptor protein tyrosine phosphatase kappa phosphatase domain 1.
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Authors
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J.Eswaran,
J.E.Debreczeni,
E.Longman,
A.J.Barr,
S.Knapp.
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Ref.
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Protein Sci, 2006,
15,
1500-1505.
[DOI no: ]
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PubMed id
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Abstract
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The receptor-type protein tyrosine phosphatases (RPTPs) are integral membrane
proteins composed of extracellular adhesion molecule-like domains, a single
transmembrane domain, and a cytoplasmic domain. The cytoplasmic domain consists
of tandem PTP domains, of which the D1 domain is enzymatically active. RPTPkappa
is a member of the R2A/IIb subfamily of RPTPs along with RPTPmu, RPTPrho, and
RPTPlambda. Here, we have determined the crystal structure of catalytically
active, monomeric D1 domain of RPTPkappa at 1.9 A. Structural comparison with
other PTP family members indicates an overall classical PTP architecture of
twisted mixed beta-sheets flanked by alpha-helices, in which the catalytically
important WPD loop is in an unhindered open conformation. Though the residues
forming the dimeric interface in the RPTPmu structure are all conserved, they
are not involved in the protein-protein interaction in RPTPkappa. The N-terminal
beta-strand, formed by betax association with betay, is conserved only in RPTPs
but not in cytosolic PTPs, and this feature is conserved in the RPTPkappa
structure forming a beta-strand. Analytical ultracentrifugation studies show
that the presence of reducing agents and higher ionic strength are necessary to
maintain RPTPkappa as a monomer. In this family the crystal structure of
catalytically active RPTPmu D1 was solved as a dimer, but the dimerization was
proposed to be a consequence of crystallization since the protein was monomeric
in solution. In agreement, we show that RPTPkappa is monomeric in solution and
crystal structure.
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Figure 2.
Figure 2. Three-dimensional structure of RPTP  . (Red)  -Helices;
(green)  -strands;
(magenta) 3[10]-helices. The helix-turn-helix segment ( 1', 2') and the
-strand formed
by association of x and y are labeled.
The corresponding conserved residues involved in dimerization of
RPTPµ are shown in ball-and-stick representation.
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The above figure is
reprinted
by permission from the Protein Society:
Protein Sci
(2006,
15,
1500-1505)
copyright 2006.
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