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Figure 3 | Cell & Bioscience

Figure 3

From: Two classes of nucleic acid translocation motors: rotation and revolution without rotation

Figure 3

Information showing the deeply rooted concept of the seemingly five-fold rotation in viral DNA packaging motors proposed several decades ago. This concept is still found in recent publications proposing a five-fold rotational phi29 DNA packaging motor (both Figure 3A and B) [1214]. The phi29 DNA packaging motor used in this figure is the same as constructed by Guo in 1986 [17, 18], who also discovered in 2013 the revolution mechanism of the phi29 motor [48] (see Figure 1, which is completely different from the five-fold rotational model). In Figure 3A, it was reported that the motor rotates in four steps [18, 19], contradictory to the traditional five-fold concept and thus requiring the supposition that one of the five subunits is inactive, resulting in a motor with only four steps of rotation [13, 14]. Interestingly, to maintain the rotation motor concept, the authors reported 1.5° rotation per bp, which corresponds to just 15.75° per complete helical turn of 10.5 bp translocated (Figure 3B) [12], while incompatible to the reality that 10.5-bp of DNA is a 360° helical pitch. (A: Adapted from [13] in Nature with permission of Nature Publishing Group; B: Adapted from [12] in Cell with permission of Elsevier).

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