Fig 1. Sequence and structural diversity of nairovirus vOTUs.
(A) Phylogenetic tree of CLUSTALW aligned nairovirus vOTUs. The tree was constructed utilizing the Jones-Thornton-Taylor model in the MEGA7 program [70]. Current species groupings are indicated by colored ovals, and the assigned species denoted. Previous serogroup classification, if applicable, is shown in parentheses. Virus vOTUs included in this study are denoted by red lettering. Inset is a structure-based phylogenetic tree of vOTUs, with the mammalian Cezanne, A20, and OTULIN OTUs included for comparison. The tree was constructed using PDB IDs 3PRP, 4HXD, 5JZE, 6DX1, 6DX2, 6DX3, 6DX5, 5LRV, 5LRX, and 3ZNZ in the MultiSeq module of VMD [71]. Sequence accession numbers are included in S1 Table. CCHFV, Crimean-Congo hemorrhagic fever virus; GANV, Ganjam virus; NSDV, Nairobi sheep disease virus; DUGV, Dugbe virus; KUPEV, Kupe virus; HAZV, Hazara virus; TFLV, Tofla virus; TAGV, Taggert virus; TILLV, Tillamook virus; SAKV, Sakhalin virus; PRMV, Paramushir virus; AVAV, Avalon virus; ARTSV, Artashat virus; TFAV, Thiafora virus; ERVEV, Erve virus; HUGV, Hughes virus; FARV, Farallon virus; RAZAV, Raza virus; PSV, Punta Salinas virus; ZIRV, Zirqa virus; SOLV, Soldado virus; GRSV, Great Saltee virus; CASV, Caspiy virus; AHV, Abu Hammad virus; DGKV, Dera Ghazi Khan virus; SAPV, Sapphire II virus; WzTV, Wēnzhōu tick virus; BURV, Burana virus; HpTV-1, Huángpí tick virus 1; TcTV-1, Tǎchéng tick virus 1; TDYV, Tamdy virus; YOGV, Yogue virus; LPHV, Leopards Hill virus; QYBV, Qalyub virus; GERV, Geran virus; CHIMV, Chim virus; GOSV, Gossas virus; ISKV, Issyk-kul virus; UZAV, Uzun-Agach virus; KTRV, Keterah virus. (B) Nairovirus vOTUs tested in this study aligned using the T-Coffee sequence alignment program [72]. Percentages show the sequence identity relative to CCHFV vOTU. Generic vOTU secondary structure based on Define Secondary Structure of Proteins (DSSP) algorithm calculations for the vOTUs is shown in reddish orange, with the α3 and α4 helices of FARV vOTU shown in teal. The catalytic triad is boxed in black and the selectivity pocket in orange. Mutation sites related to the selectivity pocket are shown by yellow stars, sites related to differences in how FARV vOTU engages mono-Ub by blue stars, and the DGKV vOTU catalytic triad mutant by a green star. Mutation sites for the second Ub binding site in FARV vOTU are denoted by red stars. The region deleted in the FARV vOTUΔ79–107 construct is indicated by a bracket.