1hm4
From Proteopedia
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[[Image:1hm4.gif|left|200px]] | [[Image:1hm4.gif|left|200px]] | ||
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'''N219L PENTALENENE SYNTHASE''' | '''N219L PENTALENENE SYNTHASE''' | ||
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[[Category: Paschall, C M.]] | [[Category: Paschall, C M.]] | ||
[[Category: Seemann, M.]] | [[Category: Seemann, M.]] | ||
| - | [[Category: | + | [[Category: Antibiotic biosynthesis]] |
| - | [[Category: | + | [[Category: Pentalenene]] |
| - | [[Category: | + | [[Category: Sesquiterpene synthase]] |
| - | [[Category: | + | [[Category: Terpene]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 19:00:16 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 16:00, 2 May 2008
N219L PENTALENENE SYNTHASE
Overview
Incubation of farnesyl diphosphate (1) with the W308F or W308F/H309F mutants of pentalenene synthase, an enzyme from Streptomyces UC5319, yielded pentalenene (2), accompanied by varying proportions of (+)-germacrene A (7) with relatively minor changes in k(cat) and k(cat)/K(m). By contrast, single H309 mutants gave rise to both (+)-germacrene A (7) and protoilludene (8) in addition to pentalenene (2). Mutation to glutamate of each of the three aspartate residues in the Mg(2+)-binding aspartate-rich domain, (80)DDLFD, resulted in reduction in the k(cat)/K(m) for farnesyl diphosphate and formation of varying proportions of pentalenene and (+)-germacrene A (7). Formation of (+)-germacrene A (7) by the various pentalenene synthase mutants is the result of a derailment of the natural anti-Markovnikov cyclization reaction, and not simply the consequence of trapping of a normally cryptic, carbocationic intermediate. Both the N219A and N219L mutants of pentalenene synthase were completely inactive, while the corresponding N219D mutant had a k(cat)/K(m) which was 3300-fold lower than that of the wild-type synthase, and produced a mixture of pentalenene (2) (91%) and the aberrant cyclization product beta-caryophyllene (9) (9%). Finally, the F77Y mutant had a k(cat)/K(m) which was reduced by 20-fold compared to that of the wild-type synthase.
About this Structure
1HM4 is a Single protein structure of sequence from Streptomyces sp.. Full crystallographic information is available from OCA.
Reference
Pentalenene synthase. Analysis of active site residues by site-directed mutagenesis., Seemann M, Zhai G, de Kraker JW, Paschall CM, Christianson DW, Cane DE, J Am Chem Soc. 2002 Jul 3;124(26):7681-9. PMID:12083921 Page seeded by OCA on Fri May 2 19:00:16 2008
