Linked Life Data

19385616

Source:http://linkedlifedata.com/resource/pubmed/id/19385616

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
18
pubmed:dateCreated
2009-5-6
pubmed:abstractText
Epi-isozizaene synthase from Streptomyces coelicolor catalyzes the multistep cyclization of farnesyl diphosphate (2, FPP) to the tricyclic sesquiterpene hydrocarbon (+)-epi-isozizaene (3), which is converted in turn to the antibiotic albaflavenone (1) in a two-step, cytochrome P450-catalyzed oxidation. Competitive incubation of deuterated and nondeuterated samples of (3S)-NPP and (3RS)-NPP followed by GC-MS analysis of the degree of deuteration in the resulting labeled epi-isozizaene established that (3R)-NPP is the natural cyclization intermediate. Incubation of (3RS)-(Z)-[1-(2)H]NPP (4b) with epi-isozizaene synthase gave [11(anti)-(2)H]epi-isozizaene (3b), indicating that the S(N)' cyclization of 4 involves the predicted anti stereochemistry, consistent with the inference from earlier experiments with chirally deuterated FPP. Incubation of separate samples of [12,12,12-(2)H(3)]FPP (2d) and [13,13,13-(2)H(3)]FPP (2e) gave epi-isozizaenes 3d and 3e, thereby establishing the stereochemical course of the cyclization of the proposed intermediate acorenyl cation 6, as well as the stereochemistry of the successive 1,2-methyl migration and deprotonation that generate the final product. Further insights into the mechanism and the role of the enzyme came from site-directed mutagenesis of active site residues in two universally conserved Mg(2+)-binding domains and the identification of six minor sesquiterpene products 9-13 and 15 produced by the wild-type and mutant proteins. The aberrant products are believed to result from derailment and premature quenching of the normal intermediates of the cationic cyclization cascade.
pubmed:grant
pubmed:commentsCorrections
http://linkedlifedata.com/resource/pubmed/commentcorrection/19385616-11827517, http://linkedlifedata.com/resource/pubmed/commentcorrection/19385616-11958631, http://linkedlifedata.com/resource/pubmed/commentcorrection/19385616-12083921, http://linkedlifedata.com/resource/pubmed/commentcorrection/19385616-12735452, http://linkedlifedata.com/resource/pubmed/commentcorrection/19385616-15186158, http://linkedlifedata.com/resource/pubmed/commentcorrection/19385616-15835903, http://linkedlifedata.com/resource/pubmed/commentcorrection/19385616-16309622, http://linkedlifedata.com/resource/pubmed/commentcorrection/19385616-16669656, http://linkedlifedata.com/resource/pubmed/commentcorrection/19385616-16895335, http://linkedlifedata.com/resource/pubmed/commentcorrection/19385616-17678871, http://linkedlifedata.com/resource/pubmed/commentcorrection/19385616-18234666, http://linkedlifedata.com/resource/pubmed/commentcorrection/19385616-8195043
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
1520-5126
pubmed:author
pubmed:issnType
Electronic
pubmed:day
13
pubmed:volume
131
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
6332-3
pubmed:dateRevised
2011-5-30
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Biosynthesis of the sesquiterpene antibiotic albaflavenone in Streptomyces coelicolor. Mechanism and stereochemistry of the enzymatic formation of epi-isozizaene.
pubmed:affiliation
Department of Chemistry, Box H, Brown University, Providence, Rhode Island 02912-9108, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural