The sliding filament hypothesis

Publication of the results in Nature, 1954

Hanson and Huxley needed to illustrate in detail the process of fibre contraction in the optical range and spent the winter of 1953-1954 painstakingly collecting light microscope pictures of each stage. These required long hours at the microscope, so much so that both researchers had to take it in turns to avoid eyestrain.

The conclusions were published in Nature in 1954 alongside similar independent results from a competing team of Andrew Huxley (no relation of HE Huxley) and Ralph Niedergerke, based in Cambridge, and who employed interference microscopy. Hanson and Huxley's paper was entitled 'Changes in the cross-striations of muscle during contraction and stretch and their structural interpretation'.

The myosin work had demonstrated that the A-bands were not after all composed of a third, mystery, substance that had apparently defeated analysis. Instead, they comprised the point of partial overlap between actin and the thicker myosin protein. Its greater density and thus higher refractive index in comparison with the rest of the muscle structure explained the A-band region's darker appearance.

The importance of the work was in combining structural and biochemical information in a coherent and satisfying hypothesis.