1wdc
From Proteopedia
(New page: 200px<br /><applet load="1wdc" size="450" color="white" frame="true" align="right" spinBox="true" caption="1wdc, resolution 2.0Å" /> '''SCALLOP MYOSIN REGULA...) |
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| - | [[Image:1wdc.gif|left|200px]]<br /><applet load="1wdc" size=" | + | [[Image:1wdc.gif|left|200px]]<br /><applet load="1wdc" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1wdc, resolution 2.0Å" /> | caption="1wdc, resolution 2.0Å" /> | ||
'''SCALLOP MYOSIN REGULATORY DOMAIN'''<br /> | '''SCALLOP MYOSIN REGULATORY DOMAIN'''<br /> | ||
==Overview== | ==Overview== | ||
| - | BACKGROUND: In contrast to the myosins of vertebrate skeletal muscle, molluscan myosins are regulated molecules whose enzymatic activity is | + | 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. |
==About this Structure== | ==About this Structure== | ||
| - | 1WDC is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Argopecten_irradians Argopecten irradians] with CA and MG as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1WDC is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Argopecten_irradians Argopecten irradians] with <scene name='pdbligand=CA:'>CA</scene> and <scene name='pdbligand=MG:'>MG</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1WDC OCA]. |
==Reference== | ==Reference== | ||
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[[Category: myosin]] | [[Category: myosin]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:43:03 2008'' |
Revision as of 13:43, 21 February 2008
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SCALLOP MYOSIN REGULATORY DOMAIN
Overview
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.
About this Structure
1WDC is a Protein complex structure of sequences from Argopecten irradians with and as ligands. Full crystallographic information is available from OCA.
Reference
Structure of the regulatory domain of scallop myosin at 2 A resolution: implications for regulation., Houdusse A, Cohen C, Structure. 1996 Jan 15;4(1):21-32. PMID:8805510
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