Dual activities of ACC synthase: Novel clues regarding the molecular evolution of <i>ACS</i> genes.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 34757795.
- Also identified by DOI 10.1126/sciadv.abg8752 and PMC identifier 8580319.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Ethylene plays profound roles in plant development. The rate-limiting enzyme of ethylene biosynthesis is 1-aminocyclopropane-1-carboxylate (ACC) synthase (ACS), which is generally believed to be a single-activity enzyme evolving from aspartate aminotransferases. Here, we demonstrate that, in addition to catalyzing the conversion of <i>S</i>-adenosyl-methionine to the ethylene precursor ACC, genuine ACSs widely have C<sub>β</sub>-S lyase activity. Two N-terminal motifs, including a glutamine residue, are essential for conferring ACS activity to ACS-like proteins. Motif and activity analyses of ACS-like proteins from plants at different evolutionary stages suggest that the ACC-dependent pathway is uniquely developed in seed plants. A putative catalytic mechanism for the dual activities of ACSs is proposed on the basis of the crystal structure and biochemical data. These findings not only expand our current understanding of ACS functions but also provide novel insights into the evolutionary origin of <i>ACS</i> genes.