The structure of Rauvolfia serpentina strictosidine synthase is a novel six-bladed β-propeller fold in plant proteins

Xueyan Ma, Santosh Panjikar, Juergen Koepke, Elke Loris, Joachim Stöckigt

Research output: Contribution to journalArticleResearchpeer-review

107 Citations (Scopus)

Abstract

The enzyme strictosidine synthase (STR1) from the Indian medicinal plant Rauvolfia serpentina is of primary importance for the biosynthetic pathway of the indole alkaloid ajmaline. Moreover, STR1 initiates all biosynthetic pathways leading to the entire monoterpenoid indole alkaloid family representing an enormous structural variety of ∼2000 compounds in higher plants. The crystal structures of STR1 in complex with its natural substrates tryptamine and secologanin provide structural understanding of the observed substrate preference and identify residues lining the active site surface that contact the substrates. STR1 catalyzes a Pictet-Spengler-type reaction and represents a novel six-bladed β-propeller fold in plant proteins. Structure-based sequence alignment revealed a common repetitive sequence motif (three hydrophobic residues are followed by a small residue and a hydrophilic residue), indicating a possible evolutionary relationship between STR1 and several sequence-unrelated six-bladed β-propeller structures. Structural analysis and site-directed mutagenesis experiments demonstrate the essential role of Glu-309 in catalysis. The data will aid in deciphering the details of the reaction mechanism of STR1 as well as other members of this enzyme family.

Original languageEnglish
Pages (from-to)907-920
Number of pages14
JournalPlant Cell
Volume18
Issue number4
DOIs
Publication statusPublished - Apr 2006
Externally publishedYes

Cite this