WT- and GOF-ADAMTS13 adopted multiple conformational states. AFM images of purified WT-ADAMTS13 (a) and GOF-ADAMTS13 (b) at pH 7.5. The horizontal scale bar is 200 nm. The vertical scale bar indicates the height. Volume (c), projected area (d) maximum length (e) and aspect ratio distribution (f) analysis of WT-ADAMTS13 (n = 369) and GOF-ADAMTS13 (n = 289) at pH 7.5. (g) The histogram of aspect ratio of WT-ADAMTS13 and GOF-ADAMTS13. The histogram of WT-ADAMTS13 was well fitted with two Gaussian distributions. The histogram of GOF-ADAMTS13 was well fitted with three Gaussian distributions.