a, Overview of the atomic structure of the dArc1 capsid with one five-fold and one two-fold capsomere highlighted. b-c, Top and side views of the five-fold and two-fold capsomeres to indicate the color coding in the following panels. d, The four different conformations of CA in the asymmetric unit aligned by either the CANTD or the CACTD domain. e, Flexibility of the four different CANTD:CANTD interfaces in the capsomeres, with the central CANTD aligned. For the adjacent CANTD Cα-RMSD: 8.6 Å. The interface accommodates relative displacements up to 55° between α1 and α2-3 in the adjacent CANTD. f, Flexibility of the four different CANTD:CACTD interfaces, with the CACTD aligned. There are only subtle movements of the neighboring residues in the CANTD relative to the CACTD. For CANTD residues involved in the interface (97-103, 117-119, 53-58), Cα-RMSD: 4.8 Å. For the full adjacent CANTD, Cα-RMSD: 6.9 Å. g, The two different conformations of the CACTD:CACTD interface. The CACTD domains forming the interfaces between adjacent capsomeres are less variable than the interfaces created between CANTD:CACTD and CANTD:CANTD shown above. Cα-RMSD for the two CTD domains forming the dimeric interface: 0.4 Å. h, Alignment of the three-fold CACTD and pseudo-three-fold CACTD axes. The histidines are positioned 6 Å apart in the true three-fold and 6 or 10 Å apart in the pseudo three-fold axes.