Characterization and functional analysis of a novel multicopper oxidase and associated polyketide biosynthesis gene cluster of aspergillus fumigatus

Download

index.pdf

Date

2007

Author

Metin, Banu

Metadata

Show full item record

Item Usage Stats

342
views

141
downloads

In this study, novel polyketide biosynthesis gene cluster of Aspergillus fumigatus was characterized and functionally analyzed. Analysis of the newly sequenced A. fumigatus genome for laccases, which are involved in melanin biosynthesis and detoxification in fungi, resulted in several putative laccase and multicopper oxidase gene sequences, one of which, Afu4g14490 (tpnJ), was selected for further characterization. The predicted amino acid sequence TpnJp showed 63% identity with the dihydrogeodin oxidase of Aspergillus terreus, which is involved in the biosynthesis of the antifungal geodin. When the genome region of tpnJ was investigated, the presence of a polyketide biosynthesis gene cluster containing 13 genes, hypothesized to be responsible for the production of trypacidin and monomethylsulochrin, was realized. By a comparative genomics approach, a putative geodin biosynthesis gene cluster containing 13 genes, including dihydrogeodin oxidase, in A. terreus and a putative trypacidin biosynthesis gene cluster containing 13 genes in N. fischeri were established. Targeted deletions of the polyketide synthase (tpnC) and multicopper oxidase (tpnJ) genes confirmed the hypothesis that TpnCp, a three-domain minimal polyketide synthase, is involved in trypacidin and monomethylsulochrin biosynthesis in A. fumigatus. TpnCp is the first fungal minimal polyketide synthase whose functional role was experimentally identified. Moreover, the fact that LC-MS analysis of DtpnJ strain showed the absence of trypacidin and the presence of a higher amount of monomethylsulochrin in DtpnJ strain, confirmed the hypothesis that TpnJp is involved in the oxidation of monomethylsulochrin into trypacidin. This novel multicopper oxidase having high substrate specificity is given the name monomethylsulochrin oxidase.

Subject Keywords

Microbiology., Food Processing and Manufacture.

URI

http://etd.lib.metu.edu.tr/upload/12609029/index.pdf
https://hdl.handle.net/11511/17485

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Characterization of extracellular beta-lactamases from penicillin G-resistant cells of Streptococcus thermophilus Chirica, LC; Güray, Nülüfer Tülün; Gültekin, Güzin Candan; Bozoglu, F (International Association for Food Protection, 1998-07-01) In this study, biochemical properties of two extracellular beta-lactamases produced by penicillin-resistant Streptococcus thermophilus cells were investigated. Both beta-lactamases showed specificity for penicillins but not for cephaloridins. The p-lactamases exhibited different affinities for penicillin G. The one with the higher molecular weight (F1) had a K(m) value of 3.44 mu M and a V(max), value of 8.33, mu mol/min/mg of protein, whereas the beta-lactamase with the lower molecular weight (FII) had a K...
Analysis of the genetic determinant for production of the pediocin P of Pediococcus pentosaecus Pep 1 Osmanagaoglu, O; Beyatli, Y; Gündüz, Ufuk; Sacilik, SC (2000-01-01) Pediococcus pentosaceus Pep1 is a vacuum-packaged Turkish sausage isolate which produces a potentially novel bacteriocin of the pediocin (anti-Listeria) family of peptides designated as pediocin P. Curing experiments and plasmid profile analysis indicated that both bacteriocin immunity and production determinants were linked and encoded by 9.0 MDa plasmid, pHD1.0. Attempts to transform purified plasmid pHD1.0 into recipient Escherichia coli JM109 cells by electroporation were successful but none of the E. c...
CHARACTERIZATION OF THE EXTRACELLULAR POLYSACCHARIDE FROM FRESH-WATER MICROALGAE CHLORELLA SP YALCIN, I; HICSASMAZ, Z; BOZ, B; BOZOGLU, F (1994-01-01) The aim of this study was the characterization of the extracellular polysaccharide (gum) from freshwater microalgae Chlorella sp. For this purpose, determination of the component monosaccharides and minerals were chosen as the structural properties, while the thickening effect on aqueous systems and the effect on the dispersed phase volume fraction of oil in water (o/w) emulsions were selected as the functional properties. The gum was found to contain the monosaccharides: glucuronic acid (385 g/kg); arabino...
Characterization of bacteriocins from two Lactococcus lactis subsp lactis isolates Akcelik, O; Tukel, C; Özcengiz, Gülay; Akcelik, M (Wiley, 2006-03-01) In this study, bacteriocins from two Lactococcus lactis subsp. lactis isolates from raw milk samples in Turkey designated OC1 and OC2, respectively, were characterized and identified. The activity spectra of the bacteriocins were determined by using different indicator bacteria including Listeria, Bacillus and Staphylococcus spp. Bacteriocins were tested for their sensitivity to different enzymes, heat treatments and pH values. Loss of bacteriocin activities after alpha-amylase treatment suggested that they...
Identification and characterization of hydrolytic enzymes from the midgut of the cotton bollworm, Helicoverpa armigera Hubner (Lepidoptera: Noctuidae) Ozgur, Ebru; Yucel, Meral; Öktem, Hüseyin Avni (2009-01-01) Midgut hydrolytic enzymes of Helicoverpa armigera Hubner (Lepidoptera: Noctuidae) were identified and partially characterized. K-m, V-max, optimum pH, and specific activity were determined for proteolytic enzymes and alpha-amylases. All hydrolytic enzyme activity had an optimum pH value in the alkaline pH range. We observed major serine protease activity, together with minor cysteine-like activity, the former being significantly inhibited by soybean trypsin inhibitor (SBTI) and aprotinin. Moreover, differen...

Citation Formats

B. Metin, “Characterization and functional analysis of a novel multicopper oxidase and associated polyketide biosynthesis gene cluster of aspergillus fumigatus,” Ph.D. - Doctoral Program, Middle East Technical University, 2007.