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

J. Biol. Chem., Vol. 283, Issue 30, 20779-20788, July 25, 2008

This Article Full Text Full Text (PDF) All Versions of this Article: 283/30/20779    most recent M802682200v1 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 Köllner, T. G. Articles by Degenhardt, J. Search for Related Content PubMed PubMed Citation Articles by Köllner, T. G. Articles by Degenhardt, J. Social Bookmarking                      What's this?

Protonation of a Neutral (S)-β-Bisabolene Intermediate Is Involved in (S)-β-Macrocarpene Formation by the Maize Sesquiterpene Synthases TPS6 and TPS11^*

Tobias G. Köllner, Christiane Schnee, Shenghong Li, Ale Svato, Bernd Schneider, Jonathan Gershenzon, and Jörg Degenhardt¹

From the Max Planck Institute for Chemical Ecology, Hans-Knöll Strasse 8, D-07745 Jena, Germany

Terpene synthases are responsible for the large diversity of terpene carbon skeletons found in plants. The unique, carbocationic reaction mechanism of these enzymes can form multiple products from a single prenyl diphosphate substrate. Two maize genes were isolated that encode very similar sesquiterpene synthases, TPS6 and TPS11, which both produce β-bisabolene, a common monocyclic sesquiterpene, and β-macrocarpene, an uncommon bicyclic olefin. Investigation of the reaction mechanism showed that the formation of β-macrocarpene proceeds via a neutral β-bisabolene intermediate and requires reprotonation by a proton that may ultimately be abstracted from water. This reprotonation is dependent on the pH and the presence of a Mg²⁺ cofactor. Mutational analysis of the enzyme demonstrated that a highly conserved tyrosine residue in the active center of the enzymes is important for the protonation process. TPS6 and TPS11 are transcribed both in leaves and roots of maize, but the respective terpene products were only detected in roots. The expression in roots was up-regulated by herbivore damage to the leaves, suggesting a long distance signal transduction cascade between leaves and roots.

Received for publication, April 7, 2008 , and in revised form, May 21, 2008.

^* The work was supported by German Research Foundation Grant DE8372-2 (to J. D. and J. G.) and funds from the Max Planck Society. 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.

The nucleotide sequence(s) reported in this paper has been submitted to the GenBank^TM/EBI Data Bank with accession number(s) AY518315 [GenBank] and EU716166.

¹ To whom correspondence should be addressed. Fax: 49-3641-571302; E-mail: degenhardt{at}ice.mpg.de.

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