This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
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...) |
|||
| Line 1: | Line 1: | ||
| - | [[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== | ||
| Line 21: | Line 21: | ||
[[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
|
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
Page seeded by OCA on Thu Feb 21 15:43:03 2008
