1jwx
From Proteopedia
(New page: 200px<br /><applet load="1jwx" size="450" color="white" frame="true" align="right" spinBox="true" caption="1jwx, resolution 1.63Å" /> '''Chalcone Synthase--F...) |
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| - | [[Image:1jwx.jpg|left|200px]]<br /><applet load="1jwx" size=" | + | [[Image:1jwx.jpg|left|200px]]<br /><applet load="1jwx" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1jwx, resolution 1.63Å" /> | caption="1jwx, resolution 1.63Å" /> | ||
'''Chalcone Synthase--F215S mutant'''<br /> | '''Chalcone Synthase--F215S mutant'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Type III polyketide synthases (PKS) generate an array of natural products | + | Type III polyketide synthases (PKS) generate an array of natural products by condensing multiple acetyl units derived from malonyl-CoA to thioester-linked starter molecules covalently bound in the PKS active site. One strategy adopted by Nature for increasing the functional diversity of these biosynthetic enzymes involves modifying polyketide assembly by altering the preference for starter molecules. Chalcone synthase (CHS) is a ubiquitous plant PKS and the first type III PKS described functionally and structurally. Guided by the three-dimensional structure of CHS, Phe-215 and Phe-265, which are situated at the active site entrance, were targeted for site-directed mutagenesis to diversify CHS activity. The resulting mutants were screened against a panel of aliphatic and aromatic CoA-linked starter molecules to evaluate the degree of starter molecule specificity in CHS. Although wild-type CHS accepts a number of natural CoA thioesters, it does not use N-methylanthraniloyl-CoA as a substrate. Substitution of Phe-215 by serine yields a CHS mutant that preferentially accepts this CoA-thioester substrate to generate a novel alkaloid, namely N-methylanthraniloyltriacetic acid lactone. These results demonstrate that a point mutation in CHS dramatically shifts the molecular selectivity of this enzyme. This structure-based approach to metabolic redesign represents an initial step toward tailoring the biosynthetic activity of plant type III PKS. |
==About this Structure== | ==About this Structure== | ||
| - | 1JWX is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Medicago_sativa Medicago sativa]. Active as [http://en.wikipedia.org/wiki/Naringenin-chalcone_synthase Naringenin-chalcone synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.3.1.74 2.3.1.74] Full crystallographic information is available from [http:// | + | 1JWX is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Medicago_sativa Medicago sativa]. Active as [http://en.wikipedia.org/wiki/Naringenin-chalcone_synthase Naringenin-chalcone synthase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.3.1.74 2.3.1.74] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1JWX OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Naringenin-chalcone synthase]] | [[Category: Naringenin-chalcone synthase]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Bowman, M | + | [[Category: Bowman, M E.]] |
| - | [[Category: Jez, J | + | [[Category: Jez, J M.]] |
| - | [[Category: Noel, J | + | [[Category: Noel, J P.]] |
[[Category: altered substrate specificity]] | [[Category: altered substrate specificity]] | ||
[[Category: ketoacyl synthase]] | [[Category: ketoacyl synthase]] | ||
[[Category: polyketide synthase]] | [[Category: polyketide synthase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:27:40 2008'' |
Revision as of 11:27, 21 February 2008
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Chalcone Synthase--F215S mutant
Overview
Type III polyketide synthases (PKS) generate an array of natural products by condensing multiple acetyl units derived from malonyl-CoA to thioester-linked starter molecules covalently bound in the PKS active site. One strategy adopted by Nature for increasing the functional diversity of these biosynthetic enzymes involves modifying polyketide assembly by altering the preference for starter molecules. Chalcone synthase (CHS) is a ubiquitous plant PKS and the first type III PKS described functionally and structurally. Guided by the three-dimensional structure of CHS, Phe-215 and Phe-265, which are situated at the active site entrance, were targeted for site-directed mutagenesis to diversify CHS activity. The resulting mutants were screened against a panel of aliphatic and aromatic CoA-linked starter molecules to evaluate the degree of starter molecule specificity in CHS. Although wild-type CHS accepts a number of natural CoA thioesters, it does not use N-methylanthraniloyl-CoA as a substrate. Substitution of Phe-215 by serine yields a CHS mutant that preferentially accepts this CoA-thioester substrate to generate a novel alkaloid, namely N-methylanthraniloyltriacetic acid lactone. These results demonstrate that a point mutation in CHS dramatically shifts the molecular selectivity of this enzyme. This structure-based approach to metabolic redesign represents an initial step toward tailoring the biosynthetic activity of plant type III PKS.
About this Structure
1JWX is a Single protein structure of sequence from Medicago sativa. Active as Naringenin-chalcone synthase, with EC number 2.3.1.74 Full crystallographic information is available from OCA.
Reference
Expanding the biosynthetic repertoire of plant type III polyketide synthases by altering starter molecule specificity., Jez JM, Bowman ME, Noel JP, Proc Natl Acad Sci U S A. 2002 Apr 16;99(8):5319-24. PMID:11959984
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