The following text describes a protein:
Function:
Non-reducing polyketide synthase; part of the gene cluster A that mediates the biosynthesis of austinol and dehydroaustinol, two fungal meroterpenoids. The first step of the pathway is the synthesis of 3,5-dimethylorsellinic acid by the polyketide synthase ausA. 3,5-dimethylorsellinic acid is then prenylated by the polyprenyl transferase ausN. Further epoxidation by the FAD-dependent monooxygenase ausM and cyclization by the probable terpene cyclase ausL lead to the formation of protoaustinoid A. Protoaustinoid A is then oxidized to spiro-lactone preaustinoid A3 by the combined action of the FAD-binding monooxygenases ausB and ausC, and the dioxygenase ausE. Acid-catalyzed keto-rearrangement and ring contraction of the tetraketide portion of preaustinoid A3 by ausJ lead to the formation of preaustinoid A4. The aldo-keto reductase ausK, with the help of ausH, is involved in the next step by transforming preaustinoid A4 into isoaustinone which is in turn hydroxylated by the P450 monooxygenase ausI to form austinolide. Finally, the cytochrome P450 monooxygenase ausG modifies austinolide to austinol. Austinol can be further modified to dehydroaustinol which forms a diffusible complex with diorcinol that initiates conidiation. Due to genetic rearrangements of the clusters and the subsequent loss of some enzymes, the end products of the Emericella nidulans austinoid biosynthesis clusters are austinol and dehydroaustinol, even if additional enzymes, such as the O-acetyltransferase ausQ and the cytochrome P450 monooxygenase ausR are still functional.
Miscellaneous:
MISCELLANEOUS: In A.calidoustus, the austinoid gene cluster lies on a contiguous DNA region, while clusters from E.nidulans and P.brasilianum are split in their respective genomes (Probable). Genetic rearrangements provoked variability among the clusters and E.nidulans produces the least number of austionoid derivatives with the end products austinol and dehydroaustinol, while P.brasilianum can produce until acetoxydehydroaustin, and A.calidoustus produces the highest number of identified derivatives (Probable).
Domain:
Multidomain protein; including a starter unit:ACP transacylase (SAT) that selects the starter unit; a ketosynthase (KS) that catalyzes repeated decarboxylative condensation to elongate the polyketide backbone; a malonyl-CoA:ACP transacylase (MAT) that selects and transfers the extender unit malonyl-CoA; a product template (PT) domain that controls the immediate cyclization regioselectivity of the reactive polyketide backbone; and an acyl-carrier protein (ACP) that serves as the tether of the growing and completed polyketide via its phosphopantetheinyl arm; The release of the polyketide chain from the non-reducing polyketide synthase is mediated by the thioesterase (TE) domain localized at the C-terminus of the protein.
Sequence:
MGSLDDNTLQQVSVLFGPKYPEVELPAGHIRRYLSNQRNANWLHDAIRDLPSVWHDILRLWPAAEKLHGDARLRQLSAFLGGGTLRPDMAEPMNFLLVPATVLRHLVDFLELKEDKNYDVCDIQGFCVGFLAAIAAACWSDNEDEFGKVVSTVLRLAVYIGAAVDLDELCEQPARSIAVRWRTAQEHKLLTEVLTRYQGAYISCVTDENAVTVTVWDSQSVSFAKELEKHGLSVKTTTLRGRFHHSNHTQAVEDILQSCERNSRLCLPSKCHKRSLPRSNINGRVCEADSLFTVAVESILTTQANWKITVTATLDNMGQSDARSIIPIGAGQFVPRHARCRMLNIVEFNKGEHINGRRKMQSATALDVGVNVTAPETTAVPIAVTGMACRYPQADSVEELWRILDLGQCTVSPMPNSRLKSGSLQREPKGPFFGNYLARPDAFDHRFFGISAREAESMDPQQRVLLQVAYEAMESAGYCGLRRSKLPDDIGCYVGVGCDDYSENVGSRNATAFSATGTLQAFNSGRISHYFGWSGPSVTVDTACSSAAVAIHLACQAIRTNDCAIAVAGGVNIMTDPRWSQNLAGASFLSPTGASKAFDADANGYCRGEGAGLLVLRPLEAALRDGDPIHAVITGTSVNQGANCSPITVPDSNSQRSLYLKALSLSGLTPDVVGYVEAHGTGTQVGDPIEFESIRKTFSGPNRATKLYVGSIKDNIGHTETSSGVAGMLKTILMIQKRRIPKQANFRRLNPRITLNERNHIEIPTQSIDWEAEKRVAMVTNYGAAGSNAAIVLREPASTPATSNSAHRETLPSHVPFYVSARTEESLRSYCEALQSTIREVAQSGTNTVQHIAYNLARKQNRDMEHFVTFPAAAGEPSELMTRLGSIASAHTQVERRSQSFHPVIICFGGQTGDTASISRNLFESCELLRFHVDECENACNALDLPSLFPAIVSPFPNKDIVNLHCVLFSIQYATAKAWLDSGLQVTRMIGHSFGQLTALCVAGGLSLIDGMRLVATRAQLIQKHWGPHTGVMLSLRASKEKVQALLDAASGHADLACLNGPDNFVVAGDEESIRRIEIIATEKGMHVELKRLKNTHAFHSRLVDAILPGLSEVANTLTFRQLDIPVEACAEQEDDWLWVTGDKIVQHSRKPVFFHDAVERTLSRVDGPCVWLEAGTASPVINMVRRVVEASRPLKSHVYLPTDLSGAQAQANLAKVTCTLWSKAVPVQFWPFHPSETGYRWINLPPYQFAKTSHWIEYNPDAFRSPPQVPDQENVQEASLVRLLRQDGKEALFTINNKDNVFRMCTAGHAVANQNLCPASLYFELVVQAALLVSSTATKPTMYHIESLNICSPLVLGMPGAVLLQLTQQDESHGQWSFVLSTRDGLQDAVTHATGRVSLQAAGSNTGICARLSSLQRLLNLASWNSIATSPSSSGLKRSTVYQAFARAVNYADYYRGVEEVYAVGHEATGRVILPSSPTKCNPCDPILIDNFIQVAGIHVNCLSETHDDEVFVCSSVGDVLIGESFVRRDTAATVPWAVYSNYEPESKKKIVCDVFVLDHTTGALAVCMLSATFTGVSIQSLKRTLNRLSNHTARPTEAEQVSINVAAEATALSSTPVAHVSSSDGDLLAVQTMLGELLGISADELSAAAALGDIGVDSLMSTEVLTEINKRFGVAISNAELTQIPDVGGLVQRIFPGHSVVRIKTHSQGAVETEITITDREPKSISVDLAPVCDTSPTAFVDKASKLFATTRTSAEFSRKTRFAGFCDTVFPQQMELVTSYVVEAFHALGADLASLTPGQVVPPVKILPQHGKVMNQLVAVLEYSDLIERRESEIIRSQQPVGTVPSLILYKKILNKHAQHASEHKLLHTTGSRLAECLSGKADPLSLLFQNAEARALMTDVYSNAPMFKSATIQLAQYLKDLLFNLGTQREIKVLEIGAGTGGTTNYLVQELAAVPGLRFQYTFTDISSSLVTLARKRFKAYDFMRYTTLDIENDPSPELQGQYDIIISTNCIHATRNLITSCTNIRRLLRPEGILCLIELTRNLFWFDLVFGLLEGWWLFNDGRSHALAHERLWDHNLRQAGFNWVDWTDNDSAESDILRLIVASSTQPFYALEGDDECEADCNTVQEQTVLYNTRDGLELFADIYYPEKTDRSGAKRPIALLIHGGGHIMLSRKEIHHEQVRMLFDMGFLPVSIDYRLCPEVSLLDGPMQDACDALAWARNKLPQLQLQRRDILPDGNNVVAVGWSTGGHLAMTLAWTAPARGVSAPEAILSFYSPTDYTDPFWSKPNFPYRVDVSTSDIQTGNPLDALQDAPISGYNPPPSKRALGGWMAPSDPRSRIALYMNWTGQTLPVLFYGCNYRARAAESGQDYEVVLPEPILSEVQKVCPFSQISAGSYRAPTFLIHGTLDDLIPVQQAQRTHDKMQACGVDSDLRIVRDGLHLFDLEANFAGNQHAFQAVVDGYEFLRRHVGL