Fig. 2: Lattice and thin filament structural parameters of skeletal muscle fibers before (blue) and after (red) cleavage of the fMyBP-C bridge region across SLs.
a A representative X-ray diffraction pattern of permeabilized fiber bundles, with key reflections and axis orientation indicated. Three different intensity scales were overlayed so that features of interest could be best viewed by the eye. X-ray pattern after 1 s exposure, with sample at 2.4 µm SL before treatment. Exemplar 1D profile plots are provided in Supplementary Fig. 3. b Schematic of the sarcomere lattice, with titin, and MyBP-C C-link points indicated, as well as the d10 lattice plane. C-links can attach to either of the two actin filaments nearby, and so this is depicted by the orange triangle. c Quantified d10. d Quantified σD, a measure of the variability in the d10 spacing. e Cartoon representation of actin, with important structural features indicated. f A6 spacing (SA6) from the right-handed actin helix. g A7 spacing (SA7) from the left-handed helix of actin. h Actin monomer spacing (SgActin), a measure of thin filament axial length. i T3 spacing (ST3) from the troponin periodicity. Statistics throughout are ANOVA designs with main effects treatment, SL, and their interaction, and a random effect of individual, followed by Tukey’s honestly significant difference (HSD) post-hoc test on statistically significant main effects (P < 0.05), and reported in figures as connecting letters: different letters are significantly different. Data throughout was reported as mean ± SE. Experimental dataset derived from 41 fiber bundles from psoas muscles of 15 SNOOPC2 mice (9 male/6 female). Further statistical details are in Supplementary Table 9.
