Comparing skeletal and cardiac calsequestrin structures and their calcium binding: a proposed mechanism for coupled calcium binding and protein polymerization

HaJeung Park; Il Yeong Park; EunJung Kim; Buhyun Youn; Kelly Fields; A Keith Dunker; ChulHee Kang

doi:10.1074/jbc.M311553200

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Comparing skeletal and cardiac calsequestrin structures and their calcium binding: a proposed mechanism for coupled calcium binding and protein polymerization

Journal article

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Peer reviewed

Comparing skeletal and cardiac calsequestrin structures and their calcium binding: a proposed mechanism for coupled calcium binding and protein polymerization

HaJeung Park, Il Yeong Park, EunJung Kim, Buhyun Youn, Kelly Fields, A Keith Dunker and ChulHee Kang

The Journal of biological chemistry, Vol.279(17), pp.18026-18033

04/23/2004

DOI: https://doi.org/10.1074/jbc.M311553200

Handle:

https://hdl.handle.net/2376/108809

PMID: 14871888

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Abstract

Amino Acid Sequence

Rabbits

Models, Molecular

Molecular Sequence Data

Crystallography, X-Ray

Ions

Muscle, Skeletal - metabolism

Calcium - chemistry

Calsequestrin - chemistry

Plasmids - metabolism

Dose-Response Relationship, Drug

Sequence Homology, Amino Acid

Spectrophotometry, Atomic

Animals

X-Ray Diffraction

Light

Myocardium - metabolism

Dogs

Escherichia coli - metabolism

Protein Binding

Scattering, Radiation

Calsequestrin - metabolism

Dimerization

Calsequestrin, the major calcium storage protein of both cardiac and skeletal muscle, binds and releases large numbers of Ca(2+) ions for each contraction and relaxation cycle. Here we show that two crystal structures for skeletal and cardiac calsequestrin are nearly superimposable not only for their subunits but also their front-to-front-type dimers. Ca(2+) binding curves were measured using atomic absorption spectroscopy. This method enables highly accurate measurements even for Ca(2+) bound to polymerized protein. The binding curves for both skeletal and cardiac calsequestrin were complex, with binding increases that correlated with protein dimerization, tetramerization, and oligomerization. The Ca(2+) binding capacities of skeletal and cardiac calsequestrin are directly compared for the first time, with approximately 80 Ca(2+) ions bound per skeletal calsequestrin and approximately 60 Ca(2+) ions per cardiac calsequestrin, as compared with net charges for these molecules of -80 and -69, respectively. Deleting the negatively charged and disordered C-terminal 27 amino acids of cardiac calsequestrin results in a 50% reduction of its calcium binding capacity and a loss of Ca(2+)-dependent tetramer formation. Based on the crystal structures of rabbit skeletal muscle calsequestrin and canine cardiac calsequestrin, Ca(2+) binding capacity data, and previous light-scattering data, a mechanism of Ca(2+) binding coupled with polymerization is proposed.

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Title: Comparing skeletal and cardiac calsequestrin structures and their calcium binding: a proposed mechanism for coupled calcium binding and protein polymerization
Creators: HaJeung Park - School of Molecular Biosciences, Washington State University, Pullman, Washington 99164-4660, USA
Il Yeong Park
EunJung Kim
Buhyun Youn
Kelly Fields
A Keith Dunker
ChulHee Kang
Publication Details: The Journal of biological chemistry, Vol.279(17), pp.18026-18033
Academic Unit: Chemistry, Department of
Publisher: United States
Identifiers: 99900547498601842
Language: English
Resource Type: Journal article