2hf5
From Proteopedia
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|PDB= 2hf5 |SIZE=350|CAPTION= <scene name='initialview01'>2hf5</scene> | |PDB= 2hf5 |SIZE=350|CAPTION= <scene name='initialview01'>2hf5</scene> | ||
|SITE= | |SITE= | ||
| - | |LIGAND= <scene name='pdbligand=CA:CALCIUM ION'>CA</scene> | + | |LIGAND= <scene name='pdbligand=CA:CALCIUM+ION'>CA</scene> |
|ACTIVITY= | |ACTIVITY= | ||
|GENE= CALM1, CALM, CAM, CAM1, CALM2, CAM2, CAMB, CALM3, CAM3, CAMC, CAMIII ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 Homo sapiens]) | |GENE= CALM1, CALM, CAM, CAM1, CALM2, CAM2, CAMB, CALM3, CAM3, CAMC, CAMIII ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 Homo sapiens]) | ||
| + | |DOMAIN= | ||
| + | |RELATEDENTRY=[[1cll|1CLL]], [[3cln|3CLN]], [[1prw|1PRW]], [[1fw4|1FW4]], [[1ak8|1AK8]] | ||
| + | |RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=2hf5 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2hf5 OCA], [http://www.ebi.ac.uk/pdbsum/2hf5 PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=2hf5 RCSB]</span> | ||
}} | }} | ||
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==Overview== | ==Overview== | ||
Calmodulin (CaM) is an EF-hand protein composed of two calcium (Ca(2+))-binding EF-hand motifs in its N-domain (EF-1 and EF-2) and two in its C-domain (EF-3 and EF-4). In this study, we examined the structure, dynamics, and Ca(2+)-binding properties of a fragment of CaM containing only EF-2 and EF-3 and the intervening linker sequence (CaM2/3). Based on NMR spectroscopic analyses, Ca(2+)-free CaM2/3 is predominantly unfolded, but upon binding Ca(2+), adopts a monomeric structure composed of two EF-hand motifs bridged by a short antiparallel beta-sheet. Despite having an "even-odd" pairing of EF-hands, the tertiary structure of CaM2/3 is similar to both the "odd-even" paired N- and C-domains of Ca(2+)-ligated CaM, with the conformationally flexible linker sequence adopting the role of an inter-EF-hand loop. However, unlike either CaM domain, CaM2/3 exhibits stepwise Ca(2+) binding with a K (d1) = 30 +/- 5 microM to EF-3, and a K (d2) > 1000 microM to EF-2. Binding of the first equivalent of Ca(2+) induces the cooperative folding of CaM2/3. In the case of native CaM, stacking interactions between four conserved aromatic residues help to hold the first and fourth helices of each EF-hand domain together, while the loop between EF-hands covalently tethers the second and third helices. In contrast, these aromatic residues lie along the second and third helices of CaM2/3, and thus are positioned adjacent to the loop between its "even-odd" paired EF-hands. This nonnative hydrophobic core packing may contribute to the weak Ca(2+) affinity exhibited by EF-2 in the context of CaM2/3. | Calmodulin (CaM) is an EF-hand protein composed of two calcium (Ca(2+))-binding EF-hand motifs in its N-domain (EF-1 and EF-2) and two in its C-domain (EF-3 and EF-4). In this study, we examined the structure, dynamics, and Ca(2+)-binding properties of a fragment of CaM containing only EF-2 and EF-3 and the intervening linker sequence (CaM2/3). Based on NMR spectroscopic analyses, Ca(2+)-free CaM2/3 is predominantly unfolded, but upon binding Ca(2+), adopts a monomeric structure composed of two EF-hand motifs bridged by a short antiparallel beta-sheet. Despite having an "even-odd" pairing of EF-hands, the tertiary structure of CaM2/3 is similar to both the "odd-even" paired N- and C-domains of Ca(2+)-ligated CaM, with the conformationally flexible linker sequence adopting the role of an inter-EF-hand loop. However, unlike either CaM domain, CaM2/3 exhibits stepwise Ca(2+) binding with a K (d1) = 30 +/- 5 microM to EF-3, and a K (d2) > 1000 microM to EF-2. Binding of the first equivalent of Ca(2+) induces the cooperative folding of CaM2/3. In the case of native CaM, stacking interactions between four conserved aromatic residues help to hold the first and fourth helices of each EF-hand domain together, while the loop between EF-hands covalently tethers the second and third helices. In contrast, these aromatic residues lie along the second and third helices of CaM2/3, and thus are positioned adjacent to the loop between its "even-odd" paired EF-hands. This nonnative hydrophobic core packing may contribute to the weak Ca(2+) affinity exhibited by EF-2 in the context of CaM2/3. | ||
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| - | ==Disease== | ||
| - | Known diseases associated with this structure: Cavernous malformations of CNS and retina OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=604214 604214]], Cerebral cavernous malformations-1 OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=604214 604214]], Hyperkeratotic cutaneous capillary-venous malformations associated with cerebral capillary malformations OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=604214 604214]], Leukemia, acute T-cell lymphoblastic OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=603025 603025]], Leukemia, acute myeloid OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=603025 603025]] | ||
==About this Structure== | ==About this Structure== | ||
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[[Category: McIntosh, L P.]] | [[Category: McIntosh, L P.]] | ||
[[Category: Reid, R E.]] | [[Category: Reid, R E.]] | ||
| - | [[Category: CA]] | ||
[[Category: calcium-binding]] | [[Category: calcium-binding]] | ||
[[Category: calmodulin]] | [[Category: calmodulin]] | ||
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[[Category: hlh]] | [[Category: hlh]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Mar 31 03:29:39 2008'' |
Revision as of 00:29, 31 March 2008
| |||||||
| Ligands: | |||||||
| Gene: | CALM1, CALM, CAM, CAM1, CALM2, CAM2, CAMB, CALM3, CAM3, CAMC, CAMIII (Homo sapiens) | ||||||
| Related: | 1CLL, 3CLN, 1PRW, 1FW4, 1AK8
| ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
The structure and function of a novel two-site calcium-binding fragment of calmodulin
Overview
Calmodulin (CaM) is an EF-hand protein composed of two calcium (Ca(2+))-binding EF-hand motifs in its N-domain (EF-1 and EF-2) and two in its C-domain (EF-3 and EF-4). In this study, we examined the structure, dynamics, and Ca(2+)-binding properties of a fragment of CaM containing only EF-2 and EF-3 and the intervening linker sequence (CaM2/3). Based on NMR spectroscopic analyses, Ca(2+)-free CaM2/3 is predominantly unfolded, but upon binding Ca(2+), adopts a monomeric structure composed of two EF-hand motifs bridged by a short antiparallel beta-sheet. Despite having an "even-odd" pairing of EF-hands, the tertiary structure of CaM2/3 is similar to both the "odd-even" paired N- and C-domains of Ca(2+)-ligated CaM, with the conformationally flexible linker sequence adopting the role of an inter-EF-hand loop. However, unlike either CaM domain, CaM2/3 exhibits stepwise Ca(2+) binding with a K (d1) = 30 +/- 5 microM to EF-3, and a K (d2) > 1000 microM to EF-2. Binding of the first equivalent of Ca(2+) induces the cooperative folding of CaM2/3. In the case of native CaM, stacking interactions between four conserved aromatic residues help to hold the first and fourth helices of each EF-hand domain together, while the loop between EF-hands covalently tethers the second and third helices. In contrast, these aromatic residues lie along the second and third helices of CaM2/3, and thus are positioned adjacent to the loop between its "even-odd" paired EF-hands. This nonnative hydrophobic core packing may contribute to the weak Ca(2+) affinity exhibited by EF-2 in the context of CaM2/3.
About this Structure
2HF5 is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Calcium-induced folding of a fragment of calmodulin composed of EF-hands 2 and 3., Lakowski TM, Lee GM, Okon M, Reid RE, McIntosh LP, Protein Sci. 2007 Jun;16(6):1119-32. Epub 2007 May 1. PMID:17473011
Page seeded by OCA on Mon Mar 31 03:29:39 2008
