Cloning and molecular analysis of radish (Raphanus sativus L.) cDNAs encoding heterodimeric γ-glutamyltransferases
γ-Glutamyltransferase (GGT) catalyzes the hydrolysis and transpeptidation of the γ-glutamyl moiety of γ-glutamyl peptides. Based on the N-terminal amino acid sequences of purified radish heterodimeric GGTs, we cloned and characterized three radish full-length cDNAs (<i>RsGGT1</i>, <i>RsGGT2</i> and <i>RsGGT3</i>) encoding putative heterodimeric GGT isoforms. RsGGT proteins contained conserved amino acid residues that are required for the catalytic activity and the post-translational processing of GGT proteins in <i>E. coli</i> and mammals. Expression analysis indicated that <i>RsGGT</i> showed different organ expression patterns. The overexpression of <i>RsGGT1</i> and <i>RsGGT2</i> cDNAs, but not that of <i>RsGGT3</i> cDNA, resulted in an increase of NaCl-extractable bound GGT activity in transgenic tobacco plants. These results suggest that <i>RsGGT1</i> and <i>RsGGT2</i> cDNAs encode heterodimeric bound GGT isoforms.
- Plant biotechnology
Plant biotechnology 23(4), 419-424, 2006-09-01
Japanese Society for Plant Cell and Molecular Biology