AXR1 (AUXIN RESISTANT 1); small protein activating enzyme. Identical to NEDD8-activating enzyme E1 regulatory subunit (AXR1) [Arabidopsis Thaliana] (GB:P42744); similar to AXL (AXR1-LIKE), catalytic [Arabidopsis thaliana] (TAIR:AT2G32410.1); similar to AXL (AXR1-LIKE), catalytic [Arabidopsis thaliana] (TAIR:AT2G32410.2); similar to auxin resistant 1 [Brassica rapa] (GB:ABV89645.1); similar to unnamed protein product [Vitis vinifera] (GB:CAO23995.1); similar to putative ubiquitin-activating enzyme (alternative splicing product) [Oryza sativa (japonica cultivar-group)] (GB:AAO65877.1); contains InterPro domain UBA/THIF-type NAD/FAD binding fol