D9N1A1 · ACTS3_ALTAL

Function

function

Highly reducing polyketide synthase; part of the gene clusters that mediate the biosynthesis of the host-selective toxins (HSTs) ACT-toxins responsible for brown spot of tangerine disease by the tangerine pathotype which affects tangerines and mandarins (PubMed:19271978).
ACT-toxins consist of three moieties, 9,10-epoxy-8-hydroxy-9-methyl-decatrienoic acid (EDA), valine and a polyketide (PubMed:22846083).
ACT-toxin I is toxic to both citrus and pear; toxin II the 5''-deoxy derivative of ACT-toxin I, is highly toxic to pear and slightly toxic to citrus (PubMed:22846083).
On cellular level, ACT-toxins affect plasma membrane of susceptible cells and cause a sudden increase in loss of K+ after a few minutes of toxin treatment (PubMed:22846083).
The acyl-CoA ligase ACTT1, the hydrolase ACTT2, the enoyl-CoA hydratases ACTT3 and ACTT6, and the acyl-CoA synthetase ACTT5 are all involved in the biosynthesis of the AK-, AF- and ACT-toxin common 9,10-epoxy-8-hydroxy-9-methyl-decatrienoic acid (EDA) structural moiety (PubMed:18944496, PubMed:18986255, PubMed:19271978).
The exact role of each enzyme, and of additional enzymes identified within the AF-toxin clusters have still to be determined (PubMed:18944496, PubMed:18986255, PubMed:19271978).
On the other hand, ACTTS1 to ACTTS4 are specific to the tangerine pathotype (PubMed:22846083).
The function of ACTTS3 is to elongate the polyketide chain portion of ACT-toxin that is unique to this toxin (PubMed:20192828).
The enoyl-reductase ACTTS2 might complement the missing enoyl-reductase (ER) domain in ACTTS3 in the synthesis of the polyketide portion of ACT-toxin (PubMed:20055645).
The roles of the nonribosomal peptide synthetases-related proteins ACTTS1 and ACTTS4 have also still not been elucidated (PubMed:22846083).

Miscellaneous

Gene clusters encoding host-selective toxins (HSTs) are localized on conditionally dispensable chromosomes (CDCs), also called supernumerary chromosomes, where they are present in multiple copies (PubMed:18986255).
The CDCs are not essential for saprophytic growth but controls host-selective pathogenicity (PubMed:18986255).
Although conventional disruption could not be accomplished due to the high number of the copies identified in the genome, the high sequence identity among these copies is likely an advantage for RNA silencing, because it allows knockdown of all copies of this gene simultaneously (PubMed:18986255).

Cofactor

pantetheine 4'-phosphate (UniProtKB | Rhea| CHEBI:47942 )

Note: Binds 1 phosphopantetheine covalently.

Pathway

Mycotoxin biosynthesis.

Features

Showing features for active site.

TypeIDPosition(s)Description
Active site179For beta-ketoacyl synthase activity
Active site316For beta-ketoacyl synthase activity
Active site356For beta-ketoacyl synthase activity
Active site641For malonyltransferase activity
Active site970Proton acceptor; for dehydratase activity
Active site1152Proton donor; for dehydratase activity

GO annotations

AspectTerm
Molecular Function3-oxoacyl-[acyl-carrier-protein] synthase activity
Molecular Functionmethyltransferase activity
Molecular Functionoxidoreductase activity
Molecular Functionphosphopantetheine binding
Biological Processfatty acid biosynthetic process
Biological Processmethylation
Biological Processsecondary metabolite biosynthetic process

Keywords

Enzyme and pathway databases

Names & Taxonomy

Protein names

  • Recommended name
    Highly reducing polyketide synthase ACTTS3
  • EC number
  • Short names
    HR-PKS ACTTS3
  • Alternative names
    • ACT-toxin biosynthesis protein S3

Gene names

    • Name
      ACTTS3

Organism names

Accessions

  • Primary accession
    D9N1A1

Organism-specific databases

Phenotypes & Variants

Disruption phenotype

Abolishes the production of ACT-toxin and leads to the loss of pathogenicity (PubMed:20192828).
Does not affect growth rate of cultures, sporulation, and spore germination (PubMed:20192828).

PTM/Processing

Features

Showing features for chain, modified residue.

TypeIDPosition(s)Description
ChainPRO_00004448551-2457Highly reducing polyketide synthase ACTTS3
Modified residue2411O-(pantetheine 4'-phosphoryl)serine

Keywords

Expression

Induction

Expression is positively regulated by CSN5 during infection.

Structure

Family & Domains

Features

Showing features for domain, region.

TypeIDPosition(s)Description
Domain5-435Ketosynthase family 3 (KS3)
Region545-856Malonyl-CoA:ACP transacylase (MAT) domain
Region938-1078N-terminal hotdog fold
Region938-1244Dehydratase (DH) domain
Domain938-1246PKS/mFAS DH
Region1091-1246C-terminal hotdog fold
Region1399-1587Methyltransferase (CMet) domain
Region2085-2281Ketoreductase (KR) domain
Domain2374-2451Carrier

Domain

Multidomain protein; including 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 dehydratase (DH) domain that reduces hydroxyl groups to enoyl groups; a methyltransferase (CMeT) domain responsible for the incorporation of methyl groups; a ketoreductase (KR) domain that catalyzes beta-ketoreduction steps; and an acyl-carrier protein (ACP) that serves as the tether of the growing and completed polyketide via its phosphopantetheinyl arm.

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    2,457
  • Mass (Da)
    271,083
  • Last updated
    2010-10-05 v1
  • Checksum
    43CF5D9695EFE055
MTPLREPIAVIGSACRFPGGANSPHKLWELLRDPRDILREFPDDRLVLSKFYNGNANHHGSTNVRNRSYLLSEDIRAFDAPFFHINPREADGMDPAQRILLEAVYEALEAAGYTMEQMQGTHTSVFVGVMNSDWWDLQMRDTETIATHAATGTARSIVSNRISYVFDLKGVSMTIDTACSSSLVALHQAVQSLRSGESTAAIVGGANILLDPAMYIAESTLQMLSPESRSRMWDKSANGYARGEGCAAVFLKPLTRAIADGDHIECVIRETGVSSDGRTQGITMPSAAAQAALIKSTYRSAGLDPLADRCQYFECHGTGTPAGDPIEAQAIAEAFFSHSGEDAEIYVGSIKTVIGHLEGCAGLAGLLKASLAIQNRTIPANMLFNDLNPLIGPYYRNLKILQAAKPWPQDIHGPRRASVNSFGFGGTNAHVILESYEPEMQGTHVLQERSFHGPLTFSACSKSSLLATISNFTSYIKTNPAVDLQNLAWVLQRKRTEFPVKQHFSGSTHARLIESMEAYLQNAGSSGLHNTTIDTKLLYPSEIPRVLGIFTGQGAQWATMGKEFIQNSYLFRESIDRSEAALVALPDPPSWSLISELFATVETSRLNEAELSQPLCTAIQIAIVDLMFAAGVKLDAVVGHSSGEIAAAYASGIISAADAMAIAYYRGFHAKRSHGTGGKRGGMVAAELSYEAALQFCEKVEWAGRLVLAASNSPSSITLSGDLDAVQEAHAYFEKENIFSRLLRVDTAYHSHHMIPCAEPYLTSLKACNIQVSQARSDCIWISSVSGDVQSSSEEQGALTGEYWVDNMVKPVLFSQAVQCSIWNSGPFESIVEIGPHFALKGPTTQVMEAVLESSPPYLSFMRRGHGIETFSDGLGRLWSKLGPSSVDLTGYWKACSSSHIKFQMLKGLPAYAWDHDKVYWKEGRISRNHRLRKDVPHELLGRRTADDSDYELRWRNVLRLTEIPWIRGHKFQGQVLFPAAGYVTMALEASKALVGDRHVRLFELRDICIRKALVLEEDQSSLETVFSVKRLNADFGIHDENMDLLEAEFSCYVCADETVGTLEKTVSGRIIIHLGSGVDVKLPPAAHFCTDLSPVDLDRFYSTVEELGLSYQGLFKGLDHAERMLNHSHALAVWENHSMGAGSMVHPALLDVMFQAIFVASISPAAPSTLWTPYLPVSIDRIIVDPDHIPVYSHPEVRAHIQAYVTKSSASSIVGDIHLLDSNGIHNGIQVEGLSLKSVAEPTEENDRSIFSQTVWDTDIASGTDFLRDRKEDAQESKLIHAIERVALFHFRSLVEAITVEKAKTLAWHHQLFLKAVKANIETIRTGGNPVVRQEWLCDTRETIEDLRAQHPGQIDLNLMHAVSEKLISIVCGETQILEVMLQDDMLNDFYMRGRGFETMNNCIARAVQQIAHKHPRAKYLEIGAGTGGTTHRILDTIESAYTSYEYTDISSAFFEKASHKFDKHASKMVFKVLDIEKDVVDQGFENGAYDVVIAANVLHATRTLSGTMGHIRSLLKPGGYLIFMEVTGDQLRLLFLFGALPGWWLGAGEGRSLGPGVSTIAWDNILRNTGFSGVDDVFYDFPDRSRHTCSVMISQAVDDQLRLLRDPLAATGMPISEQVLIIGGDTSSVSQLAYDTKRLISPWASCVAINNIDGLDSRRLPSRFSVICLTELDKPLFSEIMSEQRLSNLQNLFATANVVFWITSGCNEGTPVANMMVGIGRALATELPHLTLQFLDVKTVERLKPSIVAQSFFRLVLAKPLVMAEKSMLWTTEPELVFDGDDILIPRVLPDKEMNNRFNAARRPISENLWKESTCIELSNADNSSAPALFEIKNTIRPGETTIDVKYSVCLGKRCTFVLGVVSGTSDTVLAISDTNASSVRISKEHVFFLPHDFSGNSATLLLDTANHVLAAKLLRCISPNSIALIYEPGVRLAAAIRHHAHENTVDVFPATSNREKCGEGWAFIHPHATERDIRTIIPRNTGCFINLSFKPPGALSRALLQQTIIHGPDCLSQIVSSADGFLLEAAFNWATTGLLSLDSVETVSVQSYVGTTRPSRDFPLVFDWTAPRLPVTVKPLEPKGLFLPDKTYLMIGMTGDLGRSLCRWMAEHGARYVVLTSRNAEVDSAWIESMAAIGATVKVYKMDVSNRKSVLGVYTTIKNSLPTIAGVCNAAMVLEDRLFANMTVGALSKVFEPKVEGSKVLDEIFHELNLDFFILFSSLTSILGNGGQSNYHAANLFMTSMCAQRRARGLAASVMHIGMVADIGYVARSDRHIENHLRKLQYHPMSETDMHYLFAEAVMSSRADHPGNWNIVSGIETFVDAPGVKLRPPHYHNPRFAHYVREENARKEDLRTDKTEKSVKELLEDAISEEDVTTVFQQAFLIKLERLTQLESHRIDANKSLLNLGVDSLSAVEIRNWFLQTVGVDIPVLKLLRGDTVSEISIDATKKYLAQRTS

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
AB516321
EMBL· GenBank· DDBJ
BAJ14522.1
EMBL· GenBank· DDBJ
Genomic DNA

Similar Proteins

Disclaimer

Any medical or genetic information present in this entry is provided for research, educational and informational purposes only. It is not in any way intended to be used as a substitute for professional medical advice, diagnosis, treatment or care. Our staff consists of biologists and biochemists that are not trained to give medical advice.
We'd like to inform you that we have updated our Privacy Notice to comply with Europe’s new General Data Protection Regulation (GDPR) that applies since 25 May 2018.
FeedbackHelp