Fig. 3.

Phylogenetic tree of the six A domains (core motifs A1 to A10; 1,441 bp) of the apn gene cluster sequenced from the seven Planktothrix strains investigated. The significant bootstrap percentages were obtained from 1,000 pseudoreplicates using neighbor joining/parsimony/maximum likelihood. For each clade, the genetic dissimilarity was calculated. In addition, the position and identity of each amino acid (AA) incorporated into one of the six positions of the AP molecule are given. The NMT region (1,175 bp) of the apnC A₂ domain was not included in the phylogenetic analysis. The mcyB A₁ sequence of Microcystis strain PCC7806 served as an outgroup. Underlining indicates A domain genetic variants that were probed using the ATP-pyrophosphate exchange assay.