henylalanine was highly detected in position 1 of Anabaenopeptins isolated from terrestrial strains. Then, freshwater cyanobacteria might be promising biotechnological targets due to its highest diversity of amino acids in position 1, as the exocyclic residue is important for its inhibitory activity [12,34,45]. Concerning the variable position 3, Anabaenopeptins from freshwater and marine environments displayed a equivalent pattern of amino acid frequencies, Valine (Val) becoming essentially the most frequent, followed by Ile and L-Methionine sulfone (MetO2). In contrast, terrestrial strains generate many AP variants with Ile in position three, followed by Val and Leu, the latter being absent in this position on APs detected in aquatic environments. Homotyrosine (Hty) and Homophenylalanine (Hph) would be the most identified residues in position four among APs from all habitats analyzed, having said that, among terrestrial and marine strains Hph is additional predominantly, although Hty is typically observed in APs from freshwater strains. Except for Glycine (Gly) in some Anabaenopeptins from terrestrial strains, each of the other residues in position 5 are N-methylated. APs from non-aquatic cyanobacteria usually do not harbor homoamino acids within the fifth position and, additionally, Asparagine is only detected in a few of those variants within the respective position. Besides their detection in position five, homoamino acids seem to become much more persistent in position four from those APs analyzed. Position 6 has the highest richness of amino acids among AP variants obtained from marine environments, having incorporated 7 unique residues, BChE MedChemExpress whilst this position in variants from freshwater habitats have assimilated 9 distinctive amino acids, becoming the second most diverse web site. Such heterogeneity in the final position in APs from aquatic strains just isn’t clear, as the very first amino acid residue demonstrated to become crucial in Anabaenopeptin interaction towards its enzyme target [12,34,45]. This array of numerous amino acids detected in position 6 will not be visualized in Anabaenopeptins from terrestrial strains, where Phe was the amino acid extra detected, similar to those APs from freshwater microorganisms. The identification of the external physicochemical parameters involved within the regulation of these molecules can GSK-3 medchemexpress assist in controlling and assessing their dangers [87]. Moreover, this kind of info can allow a greater comprehension of their functions in making organisms [27,881]. Microcystins, nodularins, and saxitoxins are among by far the most studied toxins from cyanobacteria, in which their gene clusters can operate independently, getting, hence, able to react oppositely when exposed to the identical situations [92,93]. The connection between the gene cluster of Anabaenopeptins with these clusters within an individual strain is just not well explored, demanding a lot more detailed research by a holistic approach, since enabling the study of many peptides at the very same time [89,90]. Anabaenopeptins content material per cell is strongly impacted by environmental components (Figure 9). Tonk and co-workers [27] investigated the effect of light intensity, temperature, and phosphorous concentration on the growth of the cyanobacterium Anabaena sp. 90 also as its production of Anabaenopeptins A and C among some MC variants and with all the anabaenopeptilide 90 B. This later belongs to an underexplored group of depsipeptides, which equivalent for the APs has the structure of a ring having a side chain, but without the ureido linkage. In the phosphorus-limited conditi