1kas: Difference between revisions

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==Overview==

In the biosynthesis of fatty acids, the beta-ketoacyl-acyl carrier protein, (ACP) synthases catalyze chain elongation by the addition of two-carbon, units derived from malonyl-ACP to an acyl group bound to either ACP or, CoA. The crystal structure of beta-ketoacyl synthase II from Escherichia, coli has been determined with the multiple isomorphous replacement method, and refined at 2.4 A resolution. The subunit consists of two mixed, five-stranded beta-sheets surrounded by alpha-helices. The two sheets are, packed against each other in such a way that the fold can be described as, consisting of five layers, alpha-beta-alpha-beta-alpha. The enzyme is a, homodimer, and the subunits are related by a crystallographic 2-fold axis., The two active sites are located near the dimer interface but are, approximately 25 A apart. The proposed nucleophile in the reaction, Cys163, is located at the bottom of a mainly hydrophobic pocket which is, also lined with several conserved polar residues. In spite of very low, overall sequence homology, the structure of beta-ketoacyl synthase is, similar to that of thiolase, an enzyme involved in the beta-oxidation, pathway, indicating that both enzymes might have a common ancestor.

In the biosynthesis of fatty acids, the beta-ketoacyl-acyl carrier protein (ACP) synthases catalyze chain elongation by the addition of two-carbon units derived from malonyl-ACP to an acyl group bound to either ACP or CoA. The crystal structure of beta-ketoacyl synthase II from Escherichia coli has been determined with the multiple isomorphous replacement method and refined at 2.4 A resolution. The subunit consists of two mixed five-stranded beta-sheets surrounded by alpha-helices. The two sheets are packed against each other in such a way that the fold can be described as consisting of five layers, alpha-beta-alpha-beta-alpha. The enzyme is a homodimer, and the subunits are related by a crystallographic 2-fold axis. The two active sites are located near the dimer interface but are approximately 25 A apart. The proposed nucleophile in the reaction, Cys163, is located at the bottom of a mainly hydrophobic pocket which is also lined with several conserved polar residues. In spite of very low overall sequence homology, the structure of beta-ketoacyl synthase is similar to that of thiolase, an enzyme involved in the beta-oxidation pathway, indicating that both enzymes might have a common ancestor.

==About this Structure==

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[[Category: lipid metabolism]]

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@@ Line 4: / Line 4: @@
 ==Overview==
-In the biosynthesis of fatty acids, the beta-ketoacyl-acyl carrier protein, (ACP) synthases catalyze chain elongation by the addition of two-carbon, units derived from malonyl-ACP to an acyl group bound to either ACP or, CoA. The crystal structure of beta-ketoacyl synthase II from Escherichia, coli has been determined with the multiple isomorphous replacement method, and refined at 2.4 A resolution. The subunit consists of two mixed, five-stranded beta-sheets surrounded by alpha-helices. The two sheets are, packed against each other in such a way that the fold can be described as, consisting of five layers, alpha-beta-alpha-beta-alpha. The enzyme is a, homodimer, and the subunits are related by a crystallographic 2-fold axis., The two active sites are located near the dimer interface but are, approximately 25 A apart. The proposed nucleophile in the reaction, Cys163, is located at the bottom of a mainly hydrophobic pocket which is, also lined with several conserved polar residues. In spite of very low, overall sequence homology, the structure of beta-ketoacyl synthase is, similar to that of thiolase, an enzyme involved in the beta-oxidation, pathway, indicating that both enzymes might have a common ancestor.
+In the biosynthesis of fatty acids, the beta-ketoacyl-acyl carrier protein (ACP) synthases catalyze chain elongation by the addition of two-carbon units derived from malonyl-ACP to an acyl group bound to either ACP or CoA. The crystal structure of beta-ketoacyl synthase II from Escherichia coli has been determined with the multiple isomorphous replacement method and refined at 2.4 A resolution. The subunit consists of two mixed five-stranded beta-sheets surrounded by alpha-helices. The two sheets are packed against each other in such a way that the fold can be described as consisting of five layers, alpha-beta-alpha-beta-alpha. The enzyme is a homodimer, and the subunits are related by a crystallographic 2-fold axis. The two active sites are located near the dimer interface but are approximately 25 A apart. The proposed nucleophile in the reaction, Cys163, is located at the bottom of a mainly hydrophobic pocket which is also lined with several conserved polar residues. In spite of very low overall sequence homology, the structure of beta-ketoacyl synthase is similar to that of thiolase, an enzyme involved in the beta-oxidation pathway, indicating that both enzymes might have a common ancestor.
 ==About this Structure==
@@ Line 29: / Line 29: @@
 [[Category: lipid metabolism]]
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Feb  3 09:51:09 2008''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:32:04 2008''