Specific C-terminal amino acid sequence of type 2 ACC synthases is necessary for the interaction with ETO1 in the yeast two-hybrid system. Interaction of ETO1 with C-terminal mutants of LE-ACS2 deleted or swapped with LE-ACS3 were analyzed by quantitative yeast two-hybrid assay. ETO1 was cloned into pAS2 and ACS mutants were cloned into pACT2 vectors, respectively. C-terminal amino acid sequences of each mutant are shown on the left. The WVF motif and the R/D/E-rich region derived from LE-ACS3 are shown in red. The RLSF motif common to both LE-ACS3 and LE-ACS2 is shown in blue. The pACT2 vector was used as a negative control. Three independent original transformants were analyzed for each combination. Means ± SE (n = 3) are indicated.