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PDBsum entry 1n4t
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Contents |
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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Nmr structure of the forkhead-Associated domain from the arabidopsis receptor kinase-Associated protein phosphatase.
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Authors
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G.I.Lee,
Z.Ding,
J.C.Walker,
S.R.Van doren.
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Ref.
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Proc Natl Acad Sci U S A, 2003,
100,
11261-11266.
[DOI no: ]
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PubMed id
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Abstract
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Forkhead-associated (FHA) domains are phosphoprotein-binding modules found in
diverse signaling proteins that bind partners phosphorylated on threonine or
serine. Kinase-associated protein phosphatase from Arabidopsis employs its FHA
domain for negative regulation of receptor-like kinase signaling pathways, which
are important in plant development. The solution structure of the free state of
kinase-interacting FHA domain (KI-FHA) of kinase-associated protein phosphatase
has been determined with high precision and accuracy using residual dipolar
couplings. KI-FHA is a sandwich of a five-stranded mixed beta-sheet with a
six-stranded antiparallel beta-sheet. Despite homology only in the recognition
loops, this fold is shared with FHA domains from checkpoint proteins from yeast
and humans, as well as with nonhomologous MH2 domains of Smad tumor suppressors.
A shared pattern of hydrophobicity throughout FHA domains and Smad MH2 domains
may stabilize the core of the beta-sandwich. Evolutionary trace analysis of FHA
domains suggests class-specific residues in the recognition loops that could
tune their phosphoprotein-binding specificity. This surface agrees with that of
KI-FHA in contact with a phosphothreonine peptide ligand. Evolutionary trace
analysis also predicts an unexpected swath of class-specific residues on another
face of FHA domains. Protein interactions with these faces may affect assembly
of transmembrane signaling complexes in plants, and in other FHA
domain-containing assemblies.
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Figure 3.
Fig. 3. Phosphoprotein-binding surface of KI-FHA (a, b, and
c) and of FHA2 of RAD53 (d). (a) The class-specific residues at
trace level 9 are blue. (Fig. 6 summarizes the alignment of
class consensus residues at trace level 9.) The residues
identical among KAPP of maize, rice, and Arabidopsis are yellow
in a.(b) KI-FHA residues with amide NMR peaks most shifted by
saturating amounts of the pThr peptide from BAK1 (2 mM
peptide:0.5 mM KI-FHA); i.e., with   [HN] > 0.16 ppm are
red. Those residues with 0.16 ppm > [HN] > 0.06 ppm are
pink. Surface properties of KI-FHA (c) and RAD53 FHA2 (d) are
yellow for hydrophobic, blue for positively charged, and red for
negatively charged residues.
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Figure 4.
Fig. 4. Unexpected class-specific surface suggests another
interaction surface. This view is rotated 90° about the x
axis relative to Fig. 3, placing the six-stranded  -sheet in
the foreground. The color code is the same as that of Fig. 3a.
(a) The CPK surface. (b) A backbone ribbon of KI-FHA in the same
orientation as a.
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