title: Aluminum fluoride interactions with troponin C.
abstract: The increasing interest in the metal ion aluminum fluoride and beryllium fluoride complexes as phosphate analogs in the myosin ATPase reaction and in muscle fiber studies prompted the examination of their interactions with the regulatory system of troponin and tropomyosin. In this work, the effects of these metal ion analogs on the spectral properties of the Ca(2+)-binding subunit of troponin, troponin C (TnC), were examined. In contrast to beryllium fluoride which did not change the spectral properties of TnC, aluminum fluoride binding induced an increase in both the alpha-helicity and the tyrosine fluorescence of TnC and exposed a hydrophobic region on this protein for fluorescent probe binding. Aluminum fluoride also reduced the Ca2+ and/or Mg(2+)-induced changes on TnC. These results indicate a direct interaction of aluminum fluoride with TnC and merit consideration in designing muscle fiber experiments with this phosphate analog.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Los Angeles 90024.
authors.forename: B C
authors.initials: BC
authors.lastname: Phan
authors.forename: E
authors.initials: E
authors.lastname: Reisler
mesh_terms: D017607:Aluminum Compounds / Q000378:metabolism* / Q000494:pharmacology; D000817:Anilino Naphthalenesulfonates; D000818:Animals; D001608:Beryllium / Q000494:pharmacology; D001665:Binding Sites; D002118:Calcium / Q000494:pharmacology; D002942:Circular Dichroism; D004533:Egtazic Acid / Q000494:pharmacology; D005456:Fluorescent Dyes; D005459:Fluorides / Q000378:metabolism* / Q000494:pharmacology; D007700:Kinetics; D008274:Magnesium / Q000378:metabolism / Q000494:pharmacology; D009132:Muscles / Q000502:physiology; D011487:Protein Conformation / Q000187:drug effects*; D013050:Spectrometry, Fluorescence / Q000379:methods; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D014336:Troponin / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism*; D019209:Troponin C
chemical_list: D017607:Aluminum Compounds; D000817:Anilino Naphthalenesulfonates; D005456:Fluorescent Dyes; D014336:Troponin; D019209:Troponin C; C035982:beryllium fluoride; D004533:Egtazic Acid; C035763:5,5'-bis(8-(phenylamino)-1-naphthalenesulfonate); D008274:Magnesium; D001608:Beryllium; D005459:Fluorides; D002118:Calcium; C032311:aluminum fluoride