Journal of Molecular Evolution

, Volume 62, Issue 3, pp 267–280

Functional Modeling and Phylogenetic Distribution of Putative Cylindrospermopsin Biosynthesis Enzymes

Authors

  • Ralf Kellmann
    • School of Biotechnology and Biomolecular Sciences, Section MicrobiologyThe University of New South Wales, Biotechnology
  • Toby Mills
    • School of Biotechnology and Biomolecular Sciences, Section MicrobiologyThe University of New South Wales, Biotechnology
    • School of Biotechnology and Biomolecular Sciences, Section MicrobiologyThe University of New South Wales, Biotechnology
Article

DOI: 10.1007/s00239-005-0030-6

Cite this article as:
Kellmann, R., Mills, T. & Neilan, B.A. J Mol Evol (2006) 62: 267. doi:10.1007/s00239-005-0030-6

Abstract

The alkaloid cylindrospermopsin is the most recently discovered cyanotoxin and has caused epidemic outbreaks of human poisoning. Cylindrospermopsin producing cyanobacteria have in recent times appeared in countries all over the world where they had not been observed previously and, thus, represent a global public health concern. Three putative cylindrospermopsin biosynthesis genes, encoding an amidinotransferase (aoaA), a nonribosomal peptide synthetase (aoaB), and a polyketide synthase (aoaC), have been described. Most cyanotoxins are the product of nonribosomal peptide and polyketide synthesis, but the involvement of an amidinotransferase is novel. In the present study, functional modeling was carried out to gain insight into the mechanism of precursor recruitment in cylindrospermopsin biosynthesis. In addition, the molecular phylogenies of putative cylindrospermopsin biosynthesis genes and producer organisms were determined. The model indicated that AoaA may catalyze the formation of guanidino acetate from glycine and arginine. The catalytic site of the AoaB adenylation domain provided two aspartate residues, instead of the usual one, which may be involved in the binding of the guanidino moiety of guanidino acetate. Molecular phylogenetic analysis grouped cylindrospermopsin producing cyanobacteria into two divergent groups. Although the phylogeny of the cylindrospermopsin biosynthesis genes followed that of the producer organisms, they were less divergent, which may indicate the recent horizontal transfer of these genes.

Keywords

CylindrospermopsinBiosynthesis genesProtein modelingPhylogenyAmidinotransferase nonribosomal peptidePolyketide

Copyright information

© Springer Science+Business Media, Inc. 2006