Comparative Analyses of the Three-dimensional Structures and Enzymatic Properties of α, β, γ, and δ Isoforms of Ca2+-Calmodulin-dependent Protein Kinase II

Autor: Ryuji Kobayashi, Dan Wang, James K. Stoops, Steven J. Kolodziej, Tara R. Gaertner, M. Neal Waxham, John M. Koomen
Rok vydání: 2004
Předmět:
Gene isoform
Insecta
Time Factors
Light
Protein Conformation
Molecular Sequence Data
Plasma protein binding
Biology
Biochemistry
Cell Line
Adenosine Triphosphate
Protein structure
Calmodulin
Catalytic Domain
Escherichia coli
Image Processing
Computer-Assisted
Animals
Humans
Protein Isoforms
Scattering
Radiation
Amino Acid Sequence
Phosphorylation
Protein kinase A
Molecular Biology
Peptide sequence
chemistry.chemical_classification
Dose-Response Relationship
Drug
Sequence Homology
Amino Acid
Autophosphorylation
Cell Biology
Rats
Kinetics
Microscopy
Electron
Cross-Linking Reagents
Enzyme
chemistry
Spectrometry
Mass
Matrix-Assisted Laser Desorption-Ionization
Calcium-Calmodulin-Dependent Protein Kinases
Chromatography
Gel
Calcium
Calcium-Calmodulin-Dependent Protein Kinase Type 2
Peptides
Protein Binding
Zdroj: Journal of Biological Chemistry. 279:12484-12494
ISSN: 0021-9258
DOI: 10.1074/jbc.m313597200
Popis: Ca(2+)-calmodulin-dependent protein kinase II (CaM-kinase II) is a ubiquitous Ser/Thr-directed protein kinase that is expressed from a family of four genes (alpha, beta, gamma, and delta) in mammalian cells. We have documented the three-dimensional structures and the biophysical and enzymatic properties of the four gene products. Biophysical analyses showed that each isoform assembles into oligomeric forms and their three-dimensional structures at 21-25 A revealed that all four isoforms were dodecamers with similar but highly unusual architecture. A gear-shaped core comprising the association domain has the catalytic domains tethered on appendages, six of which extend from both ends of the core. At this level of resolution, we can discern no isoform-dependent differences in ultrastructure of the holoenzymes. Enzymatic analyses showed that the isoforms were similar in their K(m) for ATP and the peptide substrate syntide, but showed significant differences in their interactions with Ca(2+)-calmodulin as assessed by binding, substrate phosphorylation, and autophosphorylation. Interestingly, the rank order of CaM binding affinity (gammabetadeltaalpha) does not directly correlate with the rank order of their CaM dependence for autophosphorylation (betagammadeltaalpha). Simulations utilizing this data revealed that the measured differences in CaM binding affinities play a minor role in the autophosphorylation of the enzyme, which is largely dictated by the rate of autophosphorylation for each isoform.
Databáze: OpenAIRE
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