Linked Life Data

17068340

Source:http://linkedlifedata.com/resource/pubmed/id/17068340

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2007-1-1
pubmed:abstractText
Ammi majus L. accumulates linear furanocoumarins by cytochrome P450 (CYP)-dependent conversion of 6-prenylumbelliferone via (+)-marmesin to psoralen. Relevant activities, i.e. psoralen synthase, are induced rapidly from negligible background levels upon elicitation of A. majus cultures with transient maxima at 9-10 h and were recovered in labile microsomes. Expressed sequence tags were cloned from elicited Ammi cells by a nested DD-RT-PCR strategy with CYP-specific primers, and full-size cDNAs were generated from those fragments correlated in abundance with the induction profile of furanocoumarin-specific activities. One of these cDNAs representing a transcript of maximal abundance at 4 h of elicitation was assigned CYP71AJ1. Functional expression in Escherichia coli or yeast cells initially failed but was accomplished eventually in yeast cells after swapping the N-terminal membrane anchor domain with that of CYP73A1. The recombinant enzyme was identified as psoralen synthase with narrow substrate specificity for (+)-marmesin. Psoralen synthase catalyzes a unique carbon-chain cleavage reaction concomitantly releasing acetone by syn-elimination. Related plants, i.e. Heracleum mantegazzianum, are known to produce both linear and angular furanocoumarins by analogous conversion of 8-prenylumbelliferone via (+)-columbianetin to angelicin, and it was suggested that angelicin synthase has evolved from psoralen synthase. However, (+)-columbianetin failed as substrate but competitively inhibited psoralen synthase activity. Analogy modeling and docked solutions defined the conditions for high affinity substrate binding and predicted the minimal requirements to accommodate (+)-columbianetin in the active site cavity. The studies suggested that several point mutations are necessary to pave the road toward angelicin synthase evolution.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
5
pubmed:volume
282
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
542-54
pubmed:dateRevised
2009-7-24
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Molecular cloning and functional characterization of psoralen synthase, the first committed monooxygenase of furanocoumarin biosynthesis.
pubmed:affiliation
UMR 1121 Agronomie Environment INPL-INRA, ENSAIA, Vandoeuvre-lès-Nancy, France.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't