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PCR Mutagenesis, Cloning, Expression, Fast Protein Purification Protocols and Crystallization of the Wild Type and Mutant Forms of Tryptophan Synthase
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[Distribution of tryptophan groups in molecules of troponin T, troponin I-troponin T complex, and alpha-actinin]

A G Gvritishvili1, S O Simonishvili, N I Butkhuzi

  • 1Institute of Molecular Biology and Biololical Physics, Georgian Academy of Sciences, ul. Gotua 12, Tbilisi, 380060 Georgia.

Biofizika
|May 19, 2001
PubMed

The method of fluorescence quenching was used to experimentally determine the distribution of tryptophan residues in molecules of troponin T, troponin T-troponin I complexes, and alpha-actinin. Iodide and cesium ions, and acrylamide were used as quenchers. It was shown that cesium ions decrease the fluorescence intensity of troponin T and its complex with troponin I by the mode of dynamic quenching. For alpha-actinin such a dynamic quencher is anionic iodide. By using the modified Stern-Volmer equation, the quenching was found to be about 90% of total fluorescence intensity for troponin T, approximately 70% for the troponin T-troponin I complexes, and 20% for alpha-actinin. The penetration of cesium ions to tryptophan 206 (tryptophan 204) in the troponin T-troponin I complex is hindered, probably due to the participation of this tryptophan in the formation of bonds between troponin subunits.

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