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PDBsum entry 1wdc
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Muscle protein
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PDB id
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1wdc
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Contents |
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64 a.a.
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142 a.a.
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152 a.a.
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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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Structure of the regulatory domain of scallop myosin at 2 a resolution: implications for regulation.
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Authors
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A.Houdusse,
C.Cohen.
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Ref.
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Structure, 1996,
4,
21-32.
[DOI no: ]
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PubMed id
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Note In the PDB file this reference is
annotated as "TO BE PUBLISHED".
The citation details given above were identified by an automated
search of PubMed on title and author
names, giving a
perfect match.
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Abstract
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BACKGROUND: In contrast to the myosins of vertebrate skeletal muscle, molluscan
myosins are regulated molecules whose enzymatic activity is switched on by the
direct binding of Ca2+. The head portion (S1) of the molecule consists of a
motor domain and a regulatory domain (RD) containing a 'regulatory' and an
'essential' light chain (RLC and ELC, respectively). The structures of scallop
myosin RD with bound Ca2+, as well as the S1 fragment of chicken skeletal muscle
myosin, have been determined previously to 2.8 A resolution. RESULTS: We have
determined the structure at 2.0 A resolution of scallop myosin RD with bound
Ca2+. The unusual coordination at the specific Ca(2+)-binding site in the ELC
has now been clarified, as has the structural basis for Mg2+ binding to the RLC.
A comparison of the scallop RD structure with that in the chicken S1 structure
shows differences in the bending of the two RDs in two different places.
CONCLUSIONS: Based on these structural results, a model for regulation is
proposed in which the Ca(2+)-bound RD is a rigid structure, and transient
flexibility of the Ca(2+)-free RD allows the myosin heads to make stabilizing
intramolecular linkage which shut off the motor.
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Figure 4.
Figure 4. Stereo diagram of the complex between apo-CaM and
an IQ motif peptide. Two views are shown which are related by a
90° rotation about the horizontal axis. The helical IQ motif
peptide (black, residues Arg654-Ser686) is bent around residue
Tyr675. The N-terminal lobe of CaM (domain I in red, domain II
in yellow) adopts a closed conformation. The C-terminal lobe of
CaM (domain III in cyan, domain IV in blue) adopts a semi-open
conformation. The complex has a rather elongated shape; apo-CaM
forms a channel which surrounds the middle portion of the
peptide. On the other side of the interlobe linker (green),
interactions occur between the two lobes of CaM. Among these
linkages two hydrogen bonds are made across the peptide helix
between the sidechain of residue Glu114 (in ball-and-stick
representation) in linker 3 (purple) and backbone nitrogens of
Glu45 and Ala46 (blue balls) of linker 1.
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The above figure is
reprinted
by permission from Cell Press:
Structure
(1996,
4,
21-32)
copyright 1996.
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Secondary reference #1
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Title
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Structure of the regulatory domain of scallop myosin at 2.8 a resolution.
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Authors
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X.Xie,
D.H.Harrison,
I.Schlichting,
R.M.Sweet,
V.N.Kalabokis,
A.G.Szent-Györgyi,
C.Cohen.
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Ref.
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Nature, 1994,
368,
306-312.
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PubMed id
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Secondary reference #2
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Title
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Isolation of the regulatory domain of scallop myosin: role of the essential light chain in calcium binding.
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Authors
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H.Kwon,
E.B.Goodwin,
L.Nyitray,
E.Berliner,
E.O'Neall-Hennessey,
F.D.Melandri,
A.G.Szent-Györgyi.
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Ref.
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Proc Natl Acad Sci U S A, 1990,
87,
4771-4775.
[DOI no: ]
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PubMed id
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