Single-Jelly roll fold, horizontal
Origin:
Topology
The strands are traditionally labeled B through I for the historical reason that the first solved structure, the jelly-roll capsid protein of the tomato bushy stunt virus, had an additional strand A outside the common core of the fold. The sheets are composed of strands BIDG and CHEF, which are folded so that strand B is opposite strand C, I opposite H, and so on.(source wikipedia).
Cellular homologs of the double jelly-roll major capsid proteins clarify the origins of an ancient virus kingdom
Mart Krupovic a, Kira S Makarova b, Eugene V Koonin b
Proc Natl Acad Sci U S A. 2022 Jan 25;119(5):e2120620119.
The logic of virus evolution
Eugene V Koonin, Valerian V Dolja, Mart Krupovic
Cell Host Microbe. 2022 Jul 13;30(7):917-929.