The unprocessed preprotein form IATC103S of the isopenicillin N acyltransferase is transported inside peroxisomes and regulates its self-processing.
Previous studies in Penicillium chrysogenum and Aspergillus nidulans suggested that self-processing of the isopenicillin N acyltransferase (IAT) is an important differential factor in these fungi. Expression of a mutant penDE(C103S) gene in P. chrysogenum gave rise to an unprocessed inactive variant of IAT (IAT(C103S)) located inside peroxisomes, which indicates that transport of the proIAT inside these organelles is not dependent on the processing state of the protein. Co-expression of the penDE(C103S) and wild-type penDE genes in P. chrysogenum (Wis54-DE(C103S) strain) led to a decrease in benzylpenicillin levels. Changes in the wild-type IAT processing profile (beta subunit formation) were observed in the Wis54-DE(C103S) strain, suggesting a regulatory role of the unprocessed IAT(C103S) in the processing of the wild-type IAT. This was confirmed in Escherichia coli, where a delay in the processing of IAT in presence of the unprocessable IAT(C103S) was observed. Our results indicate that IAT is post-translationally regulated by its preprotein, which interferes with the self-processing.
García-Estrada
Carlos
C
Instituto de Biotecnología (INBIOTEC), Parque Científico de León, Av. Real, 1, 24006 León, Spain.
Vaca
Inmaculada
I
Fierro
Francisco
F
Sjollema
Klaas
K
Veenhuis
Marten
M
Martín
Juan Francisco
JF
D000217:Acyltransferases / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D025282:Mycelium / Q000648:ultrastructure; D046915:Penicillin-Binding Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D010406:Penicillins / Q000096:biosynthesis; D010408:Penicillium chrysogenum / Q000166:cytology / Q000201:enzymology* / Q000235:genetics; D020675:Peroxisomes / Q000201:enzymology*; D011498:Protein Precursors / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D021122:Protein Subunits / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D021381:Protein Transport
D005656:Fungal Proteins; D046915:Penicillin-Binding Proteins; D010406:Penicillins; D011498:Protein Precursors; D021122:Protein Subunits; D000217:Acyltransferases; C018756:acyl-CoA-6-aminopenicillanic acid acyltransferase