Fig. 1

Phylogenetic tree of soybean and human ThiF motif-containing proteins and two Arabidopsis ubiquitin E1 proteins. The unrooted phylogenetic tree was constructed by the neighbor-joining (NJ) method using MEGA 6.0 with 1000 bootstrap replicates. Arrowhead marks the gene that was cloned for verification of enzymatic activity and subsequent assays. Four soybean ThiF motif-containing proteins, Arabidopsis ubiquitin E1s and human UBE1 and UBA6 were clustered in the same clade which was encircled by broken line