MISC

2005年6月

Aspergillus parasiticus cyclase catalyzes two dehydration steps in aflatoxin biosynthesis

APPLIED AND ENVIRONMENTAL MICROBIOLOGY
  • E Sakuno
  • ,
  • Y Wen
  • ,
  • H Hatabayashi
  • ,
  • H Arai
  • ,
  • C Aoki
  • ,
  • K Yabe
  • ,
  • H Nakajima

71
6
開始ページ
2999
終了ページ
3006
記述言語
英語
掲載種別
DOI
10.1128/AEM.71.6.2999-3006.2005
出版者・発行元
AMER SOC MICROBIOLOGY

In the aflatoxin biosynthetic pathway, 5'-oxoaverantin (OAVN) cyclase, the cytosolic enzyme, catalyzes the reaction from OAVN to (2'S,5'S)-averufin (AVR) (E. Sakuno, K. Yabe, and H. Nakajima, Appl. Environ. Microbiol. 69:6418-6426, 2003). Interestingly, the N-terminal 25-amino-acid sequence of OAVN cyclase completely matched an internal sequence of the versiconal (VHOH) cyclase that was deduced from its gene (vbs). The purified OAVN cyclase also catalyzed the reaction from VHOH to versicolorin B (VB). In a competition experiment using the cytosol fraction of Aspergillus parasiticus, a high concentration of VHOH inhibited the enzyme reaction from OAVN to AVR, and instead VB was newly formed. The recombinant Vbs protein, which was expressed in Pichia pastoris, showed OAVN cyclase activity, as well as VHOH cyclase activity. A mutant,of A. parasiticus SYS-4 (= NRRL 2999) with vbs deleted accumulated large amounts of OAVN, 5'-hydroxyaverantin, averantin, AVR, and averufanin in the mycelium. These results indicated that the cyclase encoded by the vbs gene is also involved in the reaction from OAVN to AVR in aflatoxin biosynthesis. Small amounts of VHOR, VB, and aflatoxins also accumulated in the same mutant, and this accumulation may have been due to an unknown enzyme(s) not involved in aflatoxin biosynthesis. This is the first report of one enzyme catalyzing two different reactions in a pathway of secondary metabolism.

Web of Science ® 被引用回数 : 20

リンク情報
DOI
https://doi.org/10.1128/AEM.71.6.2999-3006.2005
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000229790900025&DestApp=WOS_CPL
ID情報
  • DOI : 10.1128/AEM.71.6.2999-3006.2005
  • ISSN : 0099-2240
  • Web of Science ID : WOS:000229790900025

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