(Below N is a link to NCBI taxonomic web page and E link to ESTHER at designed phylum.) > cellular organisms: NE > Bacteria: NE > Terrabacteria group: NE > Cyanobacteria/Melainabacteria group: NE > Cyanobacteria: NE > Oscillatoriophycideae: NE > Oscillatoriales: NE > Microcoleaceae: NE > Planktothrix: NE > Planktothrix agardhii: NE
Warning: This entry is a compilation of different species or line or strain with more than 90% amino acid identity. You can retrieve all strain data
(Below N is a link to NCBI taxonomic web page and E link to ESTHER at designed phylum.) Planktothrix agardhii NIVA-CYA 126/8: N, E.
Planktothrix agardhii No253: N, E.
Planktothrix agardhii CCAP 1459/16: N, E.
Planktothrix agardhii No32: N, E.
Planktothrix sp. PCC 7811: N, E.
Planktothrix agardhii SAG 6.89: N, E.
Planktothrix agardhii NIVA-CYA 68: N, E.
Planktothrix agardhii CCAP 1459/17: N, E.
Planktothrix agardhii No277: N, E.
Planktothrix agardhii No320: N, E.
Planktothrix agardhii No79: N, E.
Planktothrix agardhii No274: N, E.
Planktothrix agardhii No255: N, E.
Planktothrix agardhii No260: N, E.
Planktothrix agardhii 213: N, E.
Planktothrix agardhii No31/1: N, E.
Planktothrix agardhii No63: N, E.
Planktothrix agardhii No281: N, E.
Planktothrix agardhii No263: N, E.
Planktothrix agardhii CCAP 1459/15: N, E.
Planktothrix agardhii No66: N, E.
Planktothrix agardhii No259: N, E.
Planktothrix agardhii No39: N, E.
Planktothrix agardhii PH22: N, E.
Planktothrix agardhii No299: N, E.
Planktothrix agardhii No250: N, E.
Planktothrix agardhii No254: N, E.
Planktothrix agardhii No41: N, E.
Planktothrix agardhii CCAP 1459/11A: N, E.
Planktothrix agardhii No251: N, E.
Planktothrix agardhii CCAP 1460/5: N, E.
Planktothrix agardhii CCAP 1459/36: N, E.
Planktothrix agardhii No257: N, E.
Planktothrix agardhii 2A: N, E.
Planktothrix agardhii No307: N, E.
Planktothrix agardhii No256: N, E.
Planktothrix agardhii CCAP 1459/31: N, E.
Planktothrix prolifica NIVA-CYA 98: N, E.
Planktothrix rubescens No80: N, E.
LegendThis sequence has been compared to family alignement (MSA) red => minority aminoacid blue => majority aminoacid color intensity => conservation rate title => sequence position(MSA position)aminoacid rate Catalytic site Catalytic site in the MSA KAVFLFPPALGFATAYTNLADYLTDYTIYTFRYIADELMLEQYAELIDHL SPDQDLKLMGHSAGGFLAMLIAKKLESRDRVVSDIILLDTYRGGSETKKA DMSEIKAGVDGFLLNPKRQELRRYFLENQKLRDRTYNQVWEYFNFLWNSD LKNLQINGTIHLIRAEGNYDVEDDWIQATKGQRINYYASGVHREMIDPPY LQKNATIINSILNMGLEGLKN
BACKGROUND: Cyanobacteria often produce several different oligopeptides, with unknown biological functions, by nonribosomal peptide synthetases (NRPS). Although some cyanobacterial NRPS gene cluster types are well described, the entire NRPS genomic content within a single cyanobacterial strain has never been investigated. Here we have combined a genome-wide analysis using massive parallel pyrosequencing ("454") and mass spectrometry screening of oligopeptides produced in the strain Planktothrix rubescens NIVA CYA 98 in order to identify all putative gene clusters for oligopeptides. RESULTS: Thirteen types of oligopeptides were uncovered by mass spectrometry (MS) analyses. Microcystin, cyanopeptolin and aeruginosin synthetases, highly similar to already characterized NRPS, were present in the genome. Two novel NRPS gene clusters were associated with production of anabaenopeptins and microginins, respectively. Sequence-depth of the genome and real-time PCR data revealed three copies of the microginin gene cluster. Since NRPS gene cluster candidates for microviridin and oscillatorin synthesis could not be found, putative (gene encoded) precursor peptide sequences to microviridin and oscillatorin were found in the genes mdnA and oscA, respectively. The genes flanking the microviridin and oscillatorin precursor genes encode putative modifying enzymes of the precursor oligopeptides. We therefore propose ribosomal pathways involving modifications and cyclisation for microviridin and oscillatorin. The microviridin, anabaenopeptin and cyanopeptolin gene clusters are situated in close proximity to each other, constituting an oligopeptide island. CONCLUSION: Altogether seven nonribosomal peptide synthetase (NRPS) gene clusters and two gene clusters putatively encoding ribosomal oligopeptide biosynthetic pathways were revealed. Our results demonstrate that whole genome shotgun sequencing combined with MS-directed determination of oligopeptides successfully can identify NRPS gene clusters and the corresponding oligopeptides. The analyses suggest independent evolution of all NRPS gene clusters as functional units. Our data indicate that the Planktothrix genome displays evolution of dual pathways (NRPS and ribosomal) for production of oligopeptides in order to maximize the diversity of oligopeptides with similar but functional discrete bioactivities.
BACKGROUND: Microcystins are small cyclic heptapeptide toxins produced by a range of distantly related cyanobacteria. Microcystins are synthesized on large NRPS-PKS enzyme complexes. Many structural variants of microcystins are produced simultaneously. A recombination event between the first module of mcyB (mcyB1) and mcyC in the microcystin synthetase gene cluster is linked to the simultaneous production of microcystin variants in strains of the genus Microcystis. RESULTS: Here we undertook a phylogenetic study to investigate the order and timing of recombination between the mcyB1 and mcyC genes in a diverse selection of microcystin producing cyanobacteria. Our results provide support for complex evolutionary processes taking place at the mcyB1 and mcyC adenylation domains which recognize and activate the amino acids found at X and Z positions. We find evidence for recent recombination between mcyB1 and mcyC in strains of the genera Anabaena, Microcystis, and Hapalosiphon. We also find clear evidence for independent adenylation domain conversion of mcyB1 by unrelated peptide synthetase modules in strains of the genera Nostoc and Microcystis. The recombination events replace only the adenylation domain in each case and the condensation domains of mcyB1 and mcyC are not transferred together with the adenylation domain. Our findings demonstrate that the mcyB1 and mcyC adenylation domains are recombination hotspots in the microcystin synthetase gene cluster. CONCLUSION: Recombination is thought to be one of the main mechanisms driving the diversification of NRPSs. However, there is very little information on how recombination takes place in nature. This study demonstrates that functional peptide synthetases are created in nature through transfer of adenylation domains without the concomitant transfer of condensation domains.
Microcystins represent an extraordinarily large family of cyclic heptapeptide toxins that are nonribosomally synthesized by various cyanobacteria. Microcystins specifically inhibit the eukaryotic protein phosphatases 1 and 2A. Their outstanding variability makes them particularly useful for studies on the evolution of structure-function relationships in peptide synthetases and their genes. Analyses of microcystin synthetase genes provide valuable clues for the potential and limits of combinatorial biosynthesis. We have sequenced and analyzed 55.6 kb of the potential microcystin synthetase gene (mcy) cluster from the filamentous cyanobacterium Planktothrix agardhii CYA 126. The cluster contains genes for peptide synthetases (mcyABC), polyketide synthases (PKSs; mcyD), chimeric enzymes composed of peptide synthetase and PKS modules (mcyEG), a putative thioesterase (mcyT), a putative ABC transporter (mcyH), and a putative peptide-modifying enzyme (mcyJ). The gene content and arrangement and the sequence of specific domains in the gene products differ from those of the mcy cluster in Microcystis, a unicellular cyanobacterium. The data suggest an evolution of mcy clusters from, rather than to, genes for nodularin (a related pentapeptide) biosynthesis. Our data do not support the idea of horizontal gene transfer of complete mcy gene clusters between the genera. We have established a protocol for stable genetic transformation of Planktothrix, a genus that is characterized by multicellular filaments exhibiting continuous motility. Targeted mutation of mcyJ revealed its function as a gene coding for a O-methyltransferase. The mutant cells produce a novel microcystin variant exhibiting reduced inhibitory activity toward protein phosphatases.
