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PDBsum entry 2j5c
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References listed in PDB file
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Key reference
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Title
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Rational conversion of substrate and product specificity in a salvia monoterpene synthase: structural insights into the evolution of terpene synthase function.
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Authors
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S.C.Kampranis,
D.Ioannidis,
A.Purvis,
W.Mahrez,
E.Ninga,
N.A.Katerelos,
S.Anssour,
J.M.Dunwell,
J.Degenhardt,
A.M.Makris,
P.W.Goodenough,
C.B.Johnson.
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Ref.
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Plant Cell, 2007,
19,
1994-2005.
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PubMed id
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Abstract
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Terpene synthases are responsible for the biosynthesis of the complex chemical
defense arsenal of plants and microorganisms. How do these enzymes, which all
appear to share a common terpene synthase fold, specify the many different
products made almost entirely from one of only three substrates? Elucidation of
the structure of 1,8-cineole synthase from Salvia fruticosa (Sf-CinS1) combined
with analysis of functional and phylogenetic relationships of enzymes within
Salvia species identified active-site residues responsible for product
specificity. Thus, Sf-CinS1 was successfully converted to a sabinene synthase
with a minimum number of rationally predicted substitutions, while
identification of the Asn side chain essential for water activation introduced
1,8-cineole and alpha-terpineol activity to Salvia pomifera sabinene synthase. A
major contribution to product specificity in Sf-CinS1 appears to come from a
local deformation within one of the helices forming the active site. This
deformation is observed in all other mono- or sesquiterpene structures
available, pointing to a conserved mechanism. Moreover, a single amino acid
substitution enlarged the active-site cavity enough to accommodate the larger
farnesyl pyrophosphate substrate and led to the efficient synthesis of
sesquiterpenes, while alternate single substitutions of this critical amino acid
yielded five additional terpene synthases.
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