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OTAhal

Gene
OTAhal
Protein
Ochratoxin halogenase
Organism
Aspergillus carbonarius (strain ITEM 5010)
Length
498 amino acids
Function
Ochratoxin halogenase; part of the gene cluster that mediates the biosynthesis of ochratoxin A (OTA), a mycotoxin demonstrated to have nephrotoxic, immunotoxic, genotoxic, neurotoxic, and teratogenic properties (PubMed:24699234). OTA is composed of a chlorinated type I polyketide dihydroisocoumarin moiety linked to L-phenyl-alanine (PubMed:24699234). The highly reducing polyketide synthase (OTApks) catalyzes the formation of the isocoumarin group during the initial stages of biosynthesis, starting from one acetate and 4 malonate units, to originate the characteristic pentaketide skeleton 7-methylmellein (7-MM) of the OTA molecule (PubMed:22983973, PubMed:24699234). 7-MM is then oxidized into 7-carboxymellein (also called ochratoxin beta) (PubMed:27422838). The NRPS encoded by the OTAnrps gene is involved in the linking of phenylalanine to the dihydroisocoumarin ring (PubMed:22983973). The reaction catalyzed by NRPS results in the production of ochratoxin B (OTB), which is the non-chlorinated analog of OTA and which subsequently serves as the substrate of the halogenase (OTAhal) for chlorination activity to form the final molecular structure of OTA, containing a chlorine atom in the C-5 position of the molecule (PubMed:27422838).
Similarity
Belongs to the flavin-dependent halogenase family.
Mass
53.895 kDa
Sequence
MAIPQKATVLVIGGGPGGSYSASALAREGIDTVVLEADVFPRYHIGESLVASIRPFLKFIDLDDTFVNYGFVRKNGAAFKLNNQKEAYTDFILEAGADTFAWNVVRSESDDLMFKHAAKSGAQTFDGVRVTSIEFTDDDDDDDNNTNRPVSASWKAKDGRTGSIEFDYLVDASGRAGITSTKYLKNRTFNNYLKNVASWGYWEGATPYGMGTPVEGQPFFEALQDGSGWVWFIPLHNNTTSIGIVMNQELSTQKKKLSTTTSSRAFYLESLAGARGISRLLDPTTATLTSDIKHASDWSYNASAYGSPYLRIVGDAGAFIDPYFSSGVHLAVSGGLSAAVSIAASIRGDCPEEAAWKWHSQGVANRYGRFLLVVLGATKQIRAGDRPVLNGVGDEGFDEAFMVIRPVIQGIADVQGKVPVQDVYDAVTFSTNVVQPAAEGKRDPGWVEKARGALSHDEKEVGSVLNNLAKAYKTTDVCEGLMARLERGHLGLKLVSEV