D. Bartling et al., FUNCTIONAL EXPRESSION AND MOLECULAR CHARACTERIZATION OF ATUBC2-1, A NOVEL UBIQUITIN-CONJUGATING ENZYME (E2) FROM ARABIDOPSIS-THALIANA, Plant molecular biology, 23(2), 1993, pp. 387-396
The first member of a novel subfamily of ubiquitin-conjugating E2-prot
eins was cloned from a cDNA library of Arabidopsis thaliana. Genomic b
lots indicate that this gene family (AtUBC2) consists of two members a
nd is distinct from AtUBC1, the only other E2 enzyme known from this s
pecies to date (M.L. Sullivan and R.D. Vierstra, Proc. Natl. Acad. Sci
. USA 86 (1989) 9861-9865). The cDNA sequence of AtUBC2-1 extends over
794 bp which would encode a protein of 161 amino acids and a calculat
ed molecular mass of 18.25 kDa. The protein encoded by AtUBC2-1 is sho
wn to accept I-125-ubiquitin from wheat E1 enzymes, when expressed fro
m Escherichia coli hosts as fusion protein carrying N-terminal extensi
ons. It is deubiquitinated in the presence of lysine and, by these cri
teria, is considered a functional E2 enzyme.