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PDBsum entry 2k4d
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References listed in PDB file
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Key reference
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Title
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E2-C-Cbl recognition is necessary but not sufficient for ubiquitination activity.
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Authors
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A.Huang,
R.N.De jong,
H.Wienk,
G.S.Winkler,
H.T.Timmers,
R.Boelens.
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Ref.
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J Mol Biol, 2009,
385,
507-519.
[DOI no: ]
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PubMed id
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Abstract
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The E2 ubiquitin-conjugating enzymes UbcH7 and UbcH5B both show specific binding
to the RING (really interesting new gene) domain of the E3 ubiquitin-protein
ligase c-Cbl, but UbcH7 hardly supports ubiquitination of c-Cbl and substrate in
a reconstituted system. Here, we found that neither structural changes nor
subtle differences in the E2-E3 interaction surface are possible explanations
for the functional specificity of UbcH5B and UbcH7 in their interaction with
c-Cbl. The quick transfer of ubiquitin from the UbcH5B-Ub thioester to c-Cbl or
other ubiquitin acceptors suggests that UbcH5B might functionally be a
relatively pliable E2 enzyme. In contrast, the UbcH7-Ub thioester is too stable
to transfer ubiquitin under our assay conditions, indicating that UbcH7 might be
a more specific E2 enzyme. Our results imply that the interaction specificity
between c-Cbl and E2 is required but not sufficient for transfer of ubiquitin to
potential targets.
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Figure 3.
Fig. 3. NMR solution structure of c-Cbl linker and RING
domain (358–437). (a) Free NMR solution structure of c-Cbl
linker and RING domain. (b) The solution structure of free c-Cbl
RING finger domain (lime) superimposed on the crystal structure
of the c-Cbl RING finger domain (gray) complexed to UbcH7 (PDB
ID: 1FBV).
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Figure 7.
Fig. 7. Comparison of surface properties of UbcH5B and UbcH7.
(a) Top: electrostatic surface potential of UbcH5B was
calculated using the APBS plugin to PyMOL and indicated as a
charge scale from negative (red) to positive (blue). Bottom:
surface representation of interaction sites on UbcH5B. The
catalytic site (yellow), E2  vert,
similar Ub binding interface (cyan), E3 binding interface
(orange), and the noncovalent Ub-binding interface on UbcH5B
(green) are indicated. (b) UbcH7 electrostatic surface potential
(top) and interaction sites (bottom), colored as indicated under
(a).
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The above figures are
reprinted
by permission from Elsevier:
J Mol Biol
(2009,
385,
507-519)
copyright 2009.
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