Tm-Tn reconstitution in rabbit skeletal myofibrils. (A) Representative Coomassie blue-stained 12% SDS-PAGE gel image of the extraction and reconstitution of regulatory proteins in rabbit psoas skeletal myofibrils using D137L ααTm. Native, extracted, and D137L ααTm-Tn-reconstituted myofibrils are shown on the right. A skeletal Tn complex and D137L ααTm are shown on the left. (B) Efficiency of extraction-reconstitution with different ααTm molecules in rabbit skeletal myofibrils, averaged from a densitometry analysis of SDS-PAGE gels. Myofibrils were extracted and replaced with Tn and control, D137L, or D173L/G126R ααTm. Tm band intensities are expressed relative to the corresponding actin band. All values are given as mean ± SEM (the number of averaged gels is given above the bars). From the left, Tm/actin density ratios: native, 0.53 ± 0.01; extracted, 0.11 ± 0.01; control, 0.50 ± 0.02; D173L, 0.50 ± 0.03; D173L/G126R, 0.52 ± 0.02.