Figure 3.
Effect of TnC isoforms on isometric tension in fibres. (A) Western blot of fibre bundles from which TnC was removed with vanadate (Vi) and replaced by different isoforms. First two lanes, fibres before and after removal of TnC; following lanes, replacement with TnC isoforms indicated; last lane, F1ΔC alone. Fibre bundles did not contain equal numbers of fibres. The blot was incubated in mixed anti-TnT, -TnH and -TnC. (B) Isometric tension in native fibres in solutions with decreasing free Ca2+ (1–7); fibres were put into relaxing solution between each contraction (see Methods). (C) Fibres after vanadate treatment, showing loss of tension response. (D–G) Isometric tension in vanadate-treated fibres with added TnC: (D) F2, (E) F2mII, (F) F1, (G) F1mIV; force bar in (B) also applies to traces (D–G) and time bars are 20 min. Spikes represent fibre stretching or buffer exchange. pCa from 1 to 7: 4.7, 5.5, 5.9, 6.1, 6.3, 6.6, 6.9.