HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 283, Issue 40, 26859-26868, October 3, 2008

This Article Full Text Full Text (PDF) All Versions of this Article: 283/40/26859    most recent M804979200v1 Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Rigbers, O. Articles by Li, S.-M. Search for Related Content PubMed PubMed Citation Articles by Rigbers, O. Articles by Li, S.-M. Social Bookmarking                      What's this?

Ergot Alkaloid Biosynthesis in Aspergillus fumigatus

OVERPRODUCTION AND BIOCHEMICAL CHARACTERIZATION OF A 4-DIMETHYLALLYLTRYPTOPHAN N-METHYLTRANSFERASE^*

From the Heinrich-Heine-Universität Düsseldorf, Institut für Pharmazeutische Biologie und Biotechnologie, Universitätsstrasse 1, D-40225 Düsseldorf, Germany and the Philipps-Universität Marburg, Institut für Pharmazeutische Biologie, Deutschhausstrasse 17A, D-35037 Marburg, Germany

The putative gene fgaMT was identified in the biosynthetic gene cluster of fumigaclavines in Aspergillus fumigatus. The coding region of fgaMT was amplified by PCR from a cDNA library, cloned into pQE60, and overexpressed in Escherichia coli. FgaMT comprises 339 amino acids with a molecular mass of about 38.1 kDa. The soluble dimeric His₆-FgaMT was purified to near homogeneity and characterized biochemically. FgaMT was found to catalyze the N-methylation of 4-dimethylallyltryptophan in the presence of S-adenosylmethionine, resulting in the formation of 4-dimethylallyl-L-abrine, which was identified by NMR and mass spectrometry analysis. Therefore, FgaMT represents the second pathway-specific enzyme in the biosynthesis of ergot alkaloids. The enzyme did not require metal ions for its enzymatic reaction and showed a relatively high specificity toward the prenyl moiety at position C-4 of the indole ring. 4-Dimethylallyltryptophan derivatives with modification at the indole ring were also accepted by FgaMT as substrates. K_m values for 4-dimethylallyltryptophan and S-adenosylmethionine were determined at 0.12 and 2.4 mM, respectively. The turnover number was 2.0 s^–1.

Received for publication, June 30, 2008 , and in revised form, July 22, 2008.

^* This work was supported by a grant from the Deutsche Forschungsgemeinschaft (to S.-M. L.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

¹ To whom correspondence should be addressed. Tel.: 49-6421-2822461; Fax: 49-6421-2826678; E-mail: shu-ming.li{at}staff.uni-marburg.de.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?