Fine structure of the A-band in cryo-sections

摘要: Abstract Optical analysis of the C-zones negatively stained cryo-sectioned A-bands from human m. tibialis anterior muscle, combined with computer modelling C-zone staining pattern, has led to following conclusions. 1. (1) At a 99.9% confidence level there are two slightly different axial repeats in C-zone. One repeat 434 (± 1.2) A probably corresponds C-protein repeat, whereas other 429 (used for calibration) is due myosin crossbridges. 2. (2) The crossbridge array does not consist rows evenly spaced at 143 A. positions periodically shifted such give true repeat. 3. (3) crossbridges oriented almost perpendicular long axis muscle; extent profiles less than 80 It shown that computed model structures which explain satisfactorily appearances can also several anomalous features published X-ray diffraction patterns vertebrate muscle.