1mxe
From Proteopedia
(New page: 200px<br /><applet load="1mxe" size="450" color="white" frame="true" align="right" spinBox="true" caption="1mxe, resolution 1.70Å" /> '''Structure of the Com...) |
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| - | [[Image:1mxe.gif|left|200px]]<br /><applet load="1mxe" size=" | + | [[Image:1mxe.gif|left|200px]]<br /><applet load="1mxe" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1mxe, resolution 1.70Å" /> | caption="1mxe, resolution 1.70Å" /> | ||
'''Structure of the Complex of Calmodulin with the Target Sequence of CaMKI'''<br /> | '''Structure of the Complex of Calmodulin with the Target Sequence of CaMKI'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Calcium-saturated calmodulin (CaM) directly activates CaM-dependent | + | Calcium-saturated calmodulin (CaM) directly activates CaM-dependent protein kinase I (CaMKI) by binding to a region in the C-terminal regulatory sequence of the enzyme to relieve autoinhibition. The structure of CaM in a high-affinity complex with a 25-residue peptide of CaMKI (residues 294-318) has been determined by X-ray crystallography at 1.7 A resolution. Upon complex formation, the CaMKI peptide adopts an alpha-helical conformation, while changes in the CaM domain linker enable both its N- and C-domains to wrap around the peptide helix. Target peptide residues Trp-303 (interacting with the CaM C-domain) and Met-316 (with the CaM N-domain) define the mode of binding as 1-14. In addition, two basic patches on the peptide form complementary charge interactions with CaM. The CaM-peptide affinity is approximately 1 pM, compared with 30 nM for the CaM-kinase complex, indicating that activation of autoinhibited CaMKI by CaM requires a costly energetic disruption of the interactions between the CaM-binding sequence and the rest of the enzyme. We present biochemical and structural evidence indicating the involvement of both CaM domains in the activation process: while the C-domain exhibits tight binding toward the regulatory sequence, the N-domain is necessary for activation. Our crystal structure also enables us to identify the full CaM-binding sequence. Residues Lys-296 and Phe-298 from the target peptide interact directly with CaM, demonstrating overlap between the autoinhibitory and CaM-binding sequences. Thus, the kinase activation mechanism involves the binding of CaM to residues associated with the inhibitory pseudosubstrate sequence. |
==About this Structure== | ==About this Structure== | ||
| - | 1MXE is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Drosophila_melanogaster Drosophila melanogaster] with CA as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Calcium/calmodulin-dependent_protein_kinase Calcium/calmodulin-dependent protein kinase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.11.17 2.7.11.17] Full crystallographic information is available from [http:// | + | 1MXE is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Drosophila_melanogaster Drosophila melanogaster] with <scene name='pdbligand=CA:'>CA</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Calcium/calmodulin-dependent_protein_kinase Calcium/calmodulin-dependent protein kinase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.11.17 2.7.11.17] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1MXE OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Drosophila melanogaster]] | [[Category: Drosophila melanogaster]] | ||
[[Category: Protein complex]] | [[Category: Protein complex]] | ||
| - | [[Category: Bayley, P | + | [[Category: Bayley, P M.]] |
| - | [[Category: Clapperton, J | + | [[Category: Clapperton, J A.]] |
| - | [[Category: Gamblin, S | + | [[Category: Gamblin, S J.]] |
| - | [[Category: Martin, S | + | [[Category: Martin, S R.]] |
| - | [[Category: Smerdon, S | + | [[Category: Smerdon, S J.]] |
[[Category: CA]] | [[Category: CA]] | ||
[[Category: calmodulin]] | [[Category: calmodulin]] | ||
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[[Category: xray]] | [[Category: xray]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:00:02 2008'' |
Revision as of 12:00, 21 February 2008
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Structure of the Complex of Calmodulin with the Target Sequence of CaMKI
Overview
Calcium-saturated calmodulin (CaM) directly activates CaM-dependent protein kinase I (CaMKI) by binding to a region in the C-terminal regulatory sequence of the enzyme to relieve autoinhibition. The structure of CaM in a high-affinity complex with a 25-residue peptide of CaMKI (residues 294-318) has been determined by X-ray crystallography at 1.7 A resolution. Upon complex formation, the CaMKI peptide adopts an alpha-helical conformation, while changes in the CaM domain linker enable both its N- and C-domains to wrap around the peptide helix. Target peptide residues Trp-303 (interacting with the CaM C-domain) and Met-316 (with the CaM N-domain) define the mode of binding as 1-14. In addition, two basic patches on the peptide form complementary charge interactions with CaM. The CaM-peptide affinity is approximately 1 pM, compared with 30 nM for the CaM-kinase complex, indicating that activation of autoinhibited CaMKI by CaM requires a costly energetic disruption of the interactions between the CaM-binding sequence and the rest of the enzyme. We present biochemical and structural evidence indicating the involvement of both CaM domains in the activation process: while the C-domain exhibits tight binding toward the regulatory sequence, the N-domain is necessary for activation. Our crystal structure also enables us to identify the full CaM-binding sequence. Residues Lys-296 and Phe-298 from the target peptide interact directly with CaM, demonstrating overlap between the autoinhibitory and CaM-binding sequences. Thus, the kinase activation mechanism involves the binding of CaM to residues associated with the inhibitory pseudosubstrate sequence.
About this Structure
1MXE is a Protein complex structure of sequences from Drosophila melanogaster with as ligand. Active as Calcium/calmodulin-dependent protein kinase, with EC number 2.7.11.17 Full crystallographic information is available from OCA.
Reference
Structure of the complex of calmodulin with the target sequence of calmodulin-dependent protein kinase I: studies of the kinase activation mechanism., Clapperton JA, Martin SR, Smerdon SJ, Gamblin SJ, Bayley PM, Biochemistry. 2002 Dec 17;41(50):14669-79. PMID:12475216
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