Journal article
Recognition of β–Calcineurin by the Domains of Calmodulin: Thermodynamic and Structural Evidence for Distinct Roles
Proteins, structure, function, and bioinformatics, Vol.79(3), pp.765-786
03/2011
DOI: 10.1002/prot.22917
PMCID: PMC3057930
PMID: 21287611
Abstract
Calcineurin (CaN, PP2B, PPP3), a heterodimeric Ca
2+
-calmodulin-dependent Ser/Thr phosphatase, regulates swimming in
Paramecia
, stress responses in yeast, and T-cell activation and cardiac hypertrophy in humans. Calcium binding to CaN
B
(the regulatory subunit) triggers conformational change in CaN
A
(the catalytic subunit). Two isoforms of CaN
A
(α, β) are both abundant in brain and heart and activated by calcium-saturated calmodulin (CaM). The individual contribution of each domain of CaM to regulation of calcineurin is not known. Hydrodynamic analyses of (Ca
2+
)
4
-CaM
1-148
bound to βCaNp, a peptide representing its CaM-binding domain, indicated a 1:1 stoichiometry. βCaNp binding to CaM increased the affinity of calcium for the N- and C-domains equally, thus preserving intrinsic domain differences, and the preference of calcium for sites III and IV. The equilibrium constants for individual calcium-saturated CaM domains dissociating from βCaNp were ~1 μM. A limiting K
d
≤ 1 nM was measured directly for full-length CaM, while thermodynamic linkage analysis indicated that it was approximately 1 pM. βCaNp binding to
15
N-(Ca
2+
)
4
-CaM
1-148
monitored by
15
N/
1
HN HSQC NMR showed that association perturbed the N-domain of CaM more than its C-domain. NMR resonance assignments of CaM and βCaNp, and interpretation of intermolecular NOEs observed in the
13
C-edited and
12
C-
14
N-filtered 3D NOESY spectrum indicated anti-parallel binding. The
sole
aromatic residue (Phe) located near the βCaNp C-terminus was in close contact with several residues of the N-domain of CaM outside the hydrophobic cleft. These structural and thermodynamic properties would permit the domains of CaM to have distinct physiological roles in regulating activation of βCaN.
Details
- Title: Subtitle
- Recognition of β–Calcineurin by the Domains of Calmodulin: Thermodynamic and Structural Evidence for Distinct Roles
- Creators
- Susan E O’Donnell - Dept. of Biochemistry, Univ. of Iowa, Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242-1109Liping Yu - NMR Facility, Univ. of Iowa, Roy J. and Lucille A. Carver College of Medicine Iowa City, IA 52242-1109Andrew Fowler - NMR Facility, Univ. of Iowa, Roy J. and Lucille A. Carver College of Medicine Iowa City, IA 52242-1109Madeline A Shea - Dept. of Biochemistry, Univ. of Iowa, Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242-1109
- Resource Type
- Journal article
- Publication Details
- Proteins, structure, function, and bioinformatics, Vol.79(3), pp.765-786
- DOI
- 10.1002/prot.22917
- PMID
- 21287611
- PMCID
- PMC3057930
- NLM abbreviation
- Proteins
- ISSN
- 0887-3585
- eISSN
- 1097-0134
- Grant note
- name: University of Iowa Center for Biocatalaysis and Bioprocessing Fellowship and an American Heart Association Predoctoral Fellowship; DOI: 10.13039/100001024, name: Roy J. Carver Charitable Trust, award: 01-244; DOI: 10.13039/100000002, name: National Institutes of Health, award: RO1 GM 57001
- Language
- English
- Date published
- 03/2011
- Academic Unit
- Molecular Physiology and Biophysics; Iowa Neuroscience Institute; Biochemistry and Molecular Biology; Medicine Administration
- Record Identifier
- 9984025261602771
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