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TNP-AMP Binding to the Sarcoplasmic Reticulum Ca2+-ATPase Studied by Infrared Spectroscopy
- Source :
- Biophysical Journal. 85:3262-3270
- Publication Year :
- 2003
- Publisher :
- Elsevier BV, 2003.
-
Abstract
- Infrared spectroscopy was used to monitor the conformational change of 2',3'-O-(2,4,6-trinitrophenyl)adenosine 5'-monophosphate (TNP-AMP) binding to the sarcoplasmic reticulum Ca(2+)-ATPase. TNP-AMP binding was observed in a competition experiment: TNP-AMP is initially bound to the ATPase but is then replaced by beta,gamma-iminoadenosine 5'-triphosphate (AMPPNP) after AMPPNP release from P(3)-1-(2-nitrophenyl)ethyl AMPPNP (caged AMPPNP). The resulting infrared difference spectra are compared to those of AMPPNP binding to the free ATPase, to obtain a difference spectrum that reflects solely TNP-AMP binding to the Ca(2+)-ATPase. TNP-AMP used as an ATP analog in the crystal structure of the sarcoplasmic reticulum Ca(2+)-ATPase was found to induce a conformational change upon binding to the ATPase. It binds with a binding mode that is different from that of AMPPNP, ATP, and other tri- and diphosphate nucleotides: TNP-AMP binding causes partially opposite and smaller conformational changes compared to ATP or AMPPNP. The conformation of the TNP-AMP ATPase complex is more similar to that of the E1Ca(2) state than to that of the E1ATPCa(2) state. Regarding the use of infrared spectroscopy as a technique for ligand binding studies, our results show that infrared spectroscopy is able to distinguish different binding modes.
- Subjects :
- Conformational change
Macromolecular Substances
Protein Conformation
ATPase
Molecular Conformation
Biophysics
Infrared spectroscopy
chemical and pharmacologic phenomena
Calcium-Transporting ATPases
AMP binding
Binding, Competitive
Spectroscopy, Fourier Transform Infrared
medicine
Nucleotide
chemistry.chemical_classification
Binding Sites
biology
Endoplasmic reticulum
ATPase complex
Proteins
Adenosine
Adenosine Monophosphate
Sarcoplasmic Reticulum
Crystallography
chemistry
biology.protein
Protein Binding
medicine.drug
Subjects
Details
- ISSN :
- 00063495
- Volume :
- 85
- Database :
- OpenAIRE
- Journal :
- Biophysical Journal
- Accession number :
- edsair.doi.dedup.....04a80e649a33ac395479f72c4eab243f