These two authors have equally contributed to the study.
Characterization of Aphanizomenon ovalisporum amidinotransferase involved in cylindrospermopsin synthesis
Article first published online: 26 MAR 2013
© 2013 The Authors. Microbiology Open published by John Wiley & Sons Ltd.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Volume 2, Issue 3, pages 447–458, June 2013
How to Cite
MicrobiologyOpen 2013; 2(3): 447–458
- Issue published online: 7 JUN 2013
- Article first published online: 26 MAR 2013
- Manuscript Accepted: 6 FEB 2013
- Manuscript Revised: 26 JAN 2013
- Manuscript Received: 1 SEP 2012
- Comunidad Autónoma de Madrid
- enzyme activity;
An increasing abundance of Aphanizomenon ovalisporum in water bodies from diverse world regions has been reported in the last few years, with the majority of the isolated strains producing the toxin cylindrospermopsin (CYN), leading to a rise in ecological and health risks. The understanding of CYN synthesis is crucial in the control of CYN production. An amidinotransferase (AMDT) seems to be the first enzyme involved in the synthesis of CYN. In this study, we have cloned and overexpressed the aoaA gene from the constitutive CYN producer A. ovalisporum UAM-MAO. The recombinant purified AoaA was characterized, confirming that it is an l-arginine:glycine AMDT. It shows an optimal activity between 32 and 37°C, at pH from 8 to 9. The activity exhibits a mixed (ping-pong/sequential) kinetic mechanism, and is inhibited by the reaction product guanidine acetate (GAA) in a noncompetitive manner. Mg2+ stimulates AoaA activity while Co2+ and Mn2+ inhibit it. AoaA conserves the critical residues of the catalytic site and substrate specificity of AMDTs, as the previously reported AMDT from Cylindrospermopsis raciborskii Cyr. Both proteins can be included in a new group of prokaryotic AMDTs involved in CYN production.