Purification of a 40-kilodalton methyltransferase active in the aflatoxin biosynthetic pathway.

The penultimate step in the aflatoxin biosynthetic pathway of the filamentous fungi Aspergillus flavus and A. parasiticus involves conversion of sterigmatocystin to O-methylsterigmatocystin. An S-adenosylmethionine-dependent methyltransferase that catalyzes this reaction was purified to homogeneity...

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Auteurs principaux: Keller, N P, Dischinger, H C, Bhatnagar, D, Cleveland, T E, Ullah, A H
Format: Article
Langue:en
Publié: 1993
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Research Article
Accès en ligne:https://ncbi.nlm.nih.gov/pmc/articles/PMC202130/
https://ncbi.nlm.nih.gov/pubmed/8434913
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spelling pubmed-2021302003-12-01 Purification of a 40-kilodalton methyltransferase active in the aflatoxin biosynthetic pathway. Keller, N P Dischinger, H C Bhatnagar, D Cleveland, T E Ullah, A H Appl Environ Microbiol Research Article The penultimate step in the aflatoxin biosynthetic pathway of the filamentous fungi Aspergillus flavus and A. parasiticus involves conversion of sterigmatocystin to O-methylsterigmatocystin. An S-adenosylmethionine-dependent methyltransferase that catalyzes this reaction was purified to homogeneity (> 90%) from 78-h-old mycelia of A. parasiticus SRRC 163. Purification of this soluble enzyme was carried out by five soft-gel chromatographic steps: cell debris remover treatment, QMA ACELL chromatography, hydroxylapatite-Ultrogel chromatography, DEAE-Spherodex chromatography, and Octyl Avidgel chromatography, followed by MA7Q high-performance liquid chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the protein peak from this step on silver staining identified a single band of approximately 40 kDa. This purified protein was distinct from the dimeric 168-kDa methyltransferase purified from the same fungal strain under identical growth conditions (D. Bhatnagar, A. H. J. Ullah, and T. E. Cleveland, Prep. Biochem. 18:321-349, 1988). The chromatographic behavior and N-terminal sequence of the 40-kDa enzyme were also distinct from those of the 168-kDa methyltransferase. The molar extinction coefficient of the 40-kDa enzyme at 278 nm was estimated to be 4.7 x 10(4) M-1 cm-1 in 50 mM potassium phosphate buffer (pH 7.5). 1993-02 /pmc/articles/PMC202130/ /pubmed/8434913 Text en
institution US National Library of Medicine
collection PubMed Central
language en
format Article
topic Research Article
spellingShingle Research Article
Keller, N P
Dischinger, H C
Bhatnagar, D
Cleveland, T E
Ullah, A H
Purification of a 40-kilodalton methyltransferase active in the aflatoxin biosynthetic pathway.
description The penultimate step in the aflatoxin biosynthetic pathway of the filamentous fungi Aspergillus flavus and A. parasiticus involves conversion of sterigmatocystin to O-methylsterigmatocystin. An S-adenosylmethionine-dependent methyltransferase that catalyzes this reaction was purified to homogeneity (> 90%) from 78-h-old mycelia of A. parasiticus SRRC 163. Purification of this soluble enzyme was carried out by five soft-gel chromatographic steps: cell debris remover treatment, QMA ACELL chromatography, hydroxylapatite-Ultrogel chromatography, DEAE-Spherodex chromatography, and Octyl Avidgel chromatography, followed by MA7Q high-performance liquid chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the protein peak from this step on silver staining identified a single band of approximately 40 kDa. This purified protein was distinct from the dimeric 168-kDa methyltransferase purified from the same fungal strain under identical growth conditions (D. Bhatnagar, A. H. J. Ullah, and T. E. Cleveland, Prep. Biochem. 18:321-349, 1988). The chromatographic behavior and N-terminal sequence of the 40-kDa enzyme were also distinct from those of the 168-kDa methyltransferase. The molar extinction coefficient of the 40-kDa enzyme at 278 nm was estimated to be 4.7 x 10(4) M-1 cm-1 in 50 mM potassium phosphate buffer (pH 7.5).
author Keller, N P
Dischinger, H C
Bhatnagar, D
Cleveland, T E
Ullah, A H
author_facet Keller, N P
Dischinger, H C
Bhatnagar, D
Cleveland, T E
Ullah, A H
author_sort Keller, N P
title Purification of a 40-kilodalton methyltransferase active in the aflatoxin biosynthetic pathway.
title_short Purification of a 40-kilodalton methyltransferase active in the aflatoxin biosynthetic pathway.
title_full Purification of a 40-kilodalton methyltransferase active in the aflatoxin biosynthetic pathway.
title_fullStr Purification of a 40-kilodalton methyltransferase active in the aflatoxin biosynthetic pathway.
title_full_unstemmed Purification of a 40-kilodalton methyltransferase active in the aflatoxin biosynthetic pathway.
title_sort purification of a 40-kilodalton methyltransferase active in the aflatoxin biosynthetic pathway.
publishDate 1993
url https://ncbi.nlm.nih.gov/pmc/articles/PMC202130/
https://ncbi.nlm.nih.gov/pubmed/8434913
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