title: Exposure of actin thiols by the removal of tightly held calcium ions.
abstract: The removal of bound metal ions from G-actin uncovered two thiols, Cys-10 and Cys-257. The uncovering of these thiols requires a free calcium concentration lower than 10 nM. Therefore, participation of one or both thiols in Ca2+ binding is suggested. Actin labeled with N-(5-fluoresceinyl)maleimide in the absence of calcium moves as a doublet in NaDodSO4/PAGE. It is suggested that two conformers are induced by metal removal and labeling.
mesh_terms: D000199:Actins / Q000032:analysis* / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000032:analysis / Q000378:metabolism; D003545:Cysteine / Q000032:analysis; D005452:Fluoresceins; D010446:Peptide Fragments / Q000032:analysis; D011108:Polymers; D011485:Protein Binding; D011487:Protein Conformation; D011817:Rabbits; D013438:Sulfhydryl Compounds / Q000032:analysis; D013997:Time Factors
chemical_list: D000199:Actins; D005452:Fluoresceins; D010446:Peptide Fragments; D011108:Polymers; D013438:Sulfhydryl Compounds; C037041:fluorescein 5-maleimide; D000255:Adenosine Triphosphate; D003545:Cysteine; D002118:Calcium