A7VMU5 · AMT4_ALTAL

Function

function

Thioesterase; part of the gene clusters that mediate the biosynthesis of AM-toxins, host-selective toxins (HSTs) causing Alternaria blotch on apple, a worldwide distributed disease (PubMed:17990954).
AM-toxins are cyclic depsipeptides containing the 3 residues 2-hydroxy-isovaleric acid (2-HIV), dehydroalanine, L-alanine which are common for all 3 AM-toxins I to III. The fourth precursor is L-alpha-amino-methoxyphenyl-valeric acid (L-Amv) for AM-toxin I, L-alpha-amino-phenyl-valeric acid (L-Apv) for AM-toxin II, and L-alpha-amino-hydroxyphenyl-valeric acid (L-Ahv) for AM-toxin III (Probable). AM-toxins have two target sites for affecting susceptible apple cells; they cause invagination of the plasma membrane and electrolyte loss and chloroplast disorganization (PubMed:22846083).
The non-ribosomal peptide synthetase AMT1 contains 4 catalytic modules and is responsible for activation of each residue in AM-toxin (PubMed:10875335).
The aldo-keto reductase AMT2 catalyzes the conversion of 2-keto-isovaleric acid (2-KIV) to 2-hydroxy-isovaleric acid (2-HIV), one of the precursor residues incorporated by AMT1 during AM-toxin biosynthesis, by reduction of its ketone to an alcohol (PubMed:15066029).
The cytochrome P450 monooxygenase AMT3 and the thioesterase AMT4 are also important for AM-toxin production, but their exact function within the AM-toxin biosynthesis are not known yet (PubMed:17990954).
Up to 21 proteins (including AMT1 to AMT4) are predicted to be involved in AM-toxin biosynthesis since their expression ishighly up-regulated in AM-toxin-producing cultures (PubMed:17990954).

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:17990954).
The CDCs are not essential for saprophytic growth but controls host-selective pathogenicity (PubMed:17990954).

Pathway

Mycotoxin biosynthesis.

GO annotations

AspectTerm
Molecular Functionhydrolase activity
Biological Processbiosynthetic process

Keywords

Enzyme and pathway databases

Protein family/group databases

Names & Taxonomy

Protein names

  • Recommended name
    Thioesterase AMT4
  • EC number
  • Alternative names
    • AM-toxin biosynthesis protein 4

Gene names

    • Name
      AMT4

Organism names

Accessions

  • Primary accession
    A7VMU5

Phenotypes & Variants

Disruption phenotype

Produces smaller amounts of AM-toxin than the wild type but still causes lesions on apple leaves.

PTM/Processing

Features

Showing features for chain.

TypeIDPosition(s)Description
ChainPRO_00004448451-261Thioesterase AMT4

Expression

Induction

Expression is up-regulated more than 10 fold in toxin producing cultures.

Structure

Family & Domains

Sequence similarities

Belongs to the AMT4 thioesterase family.

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    261
  • Mass (Da)
    28,752
  • Last updated
    2007-10-23 v1
  • Checksum
    A2090383782B9FA2
MSGLDDGLENPVLIQEYSRQGRATAAPAPLVLFHDGGGTLFSYFFLESLGRDVFGFADPRATSGQQWKDGITEMAIHYYKRMKMEIRPGSVILGGWSFGGLLALQLAQMIASDSAGGFEVVGVVLIDTSCPEKASYSSTVANGPIVPFRDDVPDCMQEIVRTSMVRNTEMLSQWEAPTWPQGYSKPPILLLRAAEGIDAKEERSLKLGWELCQHDVIDSVEMVPGNHYSLFESDNIGTLSSRLRESCKRMETPYRKAASSD

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
AB525198
EMBL· GenBank· DDBJ
BAF76162.1
EMBL· GenBank· DDBJ
Genomic DNA
AB525199
EMBL· GenBank· DDBJ
BAI44766.1
EMBL· GenBank· DDBJ
Genomic DNA
AB525200
EMBL· GenBank· DDBJ
BAI44808.1
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.
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