Obituary: Professor John Michael Squire.

Working with Pradeep Luther, John's first PhD student, John and Pradeep investigated the A-bands from frog skeletal muscle which was commonly used at the time in X-ray fibre diffraction and muscle mechanics studies. He had high praise for John in his 2016 paper: "We find it remarkable that a myosin-packing scheme proposed 43 years ago based on a myosin assembly found in vertebrate smooth muscle could so accurately predict the myosin rod arrangement in insect flight muscle, a muscle about as different functionally from vertebrate smooth muscle as evolution could have produced" (Hu et al. [10]). So, it may be that John's vision of providing a detailed kinetic description of myosin head conformation during muscle contraction directly from fibre diffraction from fish muscle was hampered by instrumental limitations in the quality of the diffraction data. Keywords: Regulation of muscular contraction; Thin filament structure; Thick filament structure; X-ray diffraction; Electron microscopy EN Regulation of muscular contraction Thin filament structure Thick filament structure X-ray diffraction Electron microscopy 125 132 8 10/04/23 20230901 NES 230901 Graph John Michael Squire passed away on 31st January 2021, a victim of the Covid-19 pandemic. [Extracted from the article]