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Figure 3.
Figure 3. Novel Conformations and Movement of the Catalytic
(WPD) Loop
(A) WPD loop conformations are shown by a PTP
representative of each state: closed (blue, PTP1B, PDB: 1SUG);
open (yellow, PTP1B, PDB: 2HNP); and atypical (magenta, GLEPP1,
PDB: 2GJT; STEP, PDB: 2BIJ; Lyp, PDB: 2P6X). The intermediate
WPD loop conformation of PCPTP1 (PDB: 2A8B) is not shown for
clarity. Other PTP structures are shown with a thin transparent
line tracing the backbone and are colored according to
conformation.
(B) Superimposition of the structure of
STEP-C/S in complex with pY (PDB: 2CJZ; gray) and the apo STEP
(PDB: 2BIJ; light green) showing that the WPD loop conformation
does not change on substrate binding (pTyr, orange). The
catalytic water molecule (Wa) corresponding to that found in
closed structures is shown.
(C) Superimposition of the
structure of STEP-C/S in complex with pY (PDB: 2CJZ; green) and
PTP1B with the insulin receptor peptide (PDB: 1G1H; red). The
conserved water molecule found in closed structures is shown:
PTP1B (1SUG, yellow); GLEPP1 (2G59, orange); HePTP (2A3K,
black), DEP1 (2NZ6, magenta). The arrow indicates the position
of the displaced water molecule in STEP-C/S structure.
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