Two oxygenase genes, Tanespimycin O18 and O19, proposed to encode a monooxygenase and a Rieske-type oxygenase, were identified in the wel gene clusters from WI HT-29-1 and FM SAG1427-1. Further biochemical investigation

is required to determine the specific role of each oxygenase to their respective pathway. Table 3 List of encoded oxygenase enzymes from the hpi , amb and wel biosynthetic gene clusters Enzyme FS ATCC 43239 FS PCC 9339 FA UTEX 1903 HW IC-52-3 WI HT-29-1 FS PCC 9431 FM SAG 1427-1 % identity Oxygenases                 Rieske oxygenase – - AmbO1 – - – - – Rieske oxygenase – - AmbO2 – - – - – Rieske oxygenase – - AmbO3 – - – - – Rieske oxygenase – HpiO4 AmbO4 – - – - 100 Oxidoreductase, 2OG-Fe(II) oxygenase family – HpiO5 AmbO5 – - – - 98.1 Alkanesulfonate monooxygenase – HpiO6 AmbO6 – - – - 100 Oxidoreductase, find more FAD dependent pyridine nucleotide disulfide – - AmbO7 – - – - – Rieske oxygenase HpiO8 HpiO8 – - – - – 100 Rieske oxygenase HpiO9 – - – - – - – Oxidoreductase, FAD dependent HpiO10 – - – - – - – Rieske oxygenase – - – WelO11

WelO11 – - 90.9 Rieske oxygenase – - – WelO12 WelO12 WelO12 – 99.1 Rieske oxygenase – - – WelO13 WelO13 –   97.8 Rieske oxygenase – - – WelO14 WelO14 WelO14 – 98.1 Oxidoreductase, 2OG-Fe(II) oxygenase family – - – WelO15 WelO15 WelO15 – 96.3 Indoleamine 2,3-dioxygenase – - – WelO16 WelO16 WelO16 – 99.0 Choline dehydrogenase-like CH5183284 cost flavoprotein – - – WelO17 WelO17 WelO17 – 99.0 Monooxygenase – - – - WelO18 – WelO18 99.0 Rieske oxygenase – - – - WelO19 – WelO19 98.3 Genes containing a domain of unknown function Another common feature of the hpi/amb/wel gene clusters is the presence of DUF genes. 21 DUF genes were identified from all of the gene clusters (excluding HW UTEXB1830) and each protein sequence was compared to each other and those with an identity greater than 90% were labelled with the same number (Additional

file 10). A total of eight different genes (U1-8) were identified (Table 4). Although one DUF gene was not found in all Morin Hydrate gene clusters, U6 was identified in all of the hpi and wel gene clusters. U1-3 were identified in both the hpi and amb gene clusters, and U4 was identified in the hpi gene cluster from FS PCC9339 and the amb gene cluster. U5 was identified exclusively in the hpi gene cluster from FS ATCC43239, U7 was identified only in the wel gene cluster from HW IC-52-3, and U8 was identified in the wel gene clusters from HW IC-52-3, WI HT-29-1 and FS PCC9431. However, as the function of these protein-encoding genes remains unknown, their involvement in the biosynthesis of the hapalindole, fischerindoles, ambiguines and welwitindolinones remains elusive. Table 4 List of unknown proteins with domain of unknown function from hpi , amb and wel clusters Enzyme FS ATCC 43239 FS PCC 9339 FA UTEX 1903 HW IC-52-3 WI HT-29-1 FS PCC 9431 FM SAG 1427-1 % identity Unknown proteins with DUF                 Unknown function HpiU1 HpiU1 AmbU1 – - – - 97.