1mej: Difference between revisions

Revision as of 14:54, 21 February 2008

Human Glycinamide Ribonucleotide Transformylase domain at pH 8.5

OverviewOverview

Glycinamide ribonucleotide transformylase (GAR Tfase) is a key folate-dependent enzyme in the de novo purine biosynthesis pathway and, as such, has been the target for antitumor drug design. Here, we describe the crystal structures of the human GAR Tfase (purN) component of the human trifunctional protein (purD-purM-purN) at various pH values and in complex with its substrate. Human GAR Tfase exhibits pH-dependent enzyme activity with its maximum around pH 7.5-8. Comparison of unliganded human GAR Tfase structures at pH 4.2 and pH 8.5 reveals conformational differences in the substrate binding loop, which at pH 4.2 occupies the binding cleft and prohibits substrate binding, while at pH 8.5 is permissive for substrate binding. The crystal structure of GAR Tfase with its natural substrate, beta-glycinamide ribonucleotide (beta-GAR), at pH 8.5 confirms this conformational isomerism. Surprisingly, several important structural differences are found between human GAR Tfase and previously reported E. coli GAR Tfase structures, which have been used as the primary template for drug design studies. While the E. coli structure gave valuable insights into the active site and formyl transfer mechanism, differences in structure and inhibition between the bacterial and mammalian enzymes suggest that the human GAR Tfase structure is now the appropriate template for the design of anti-cancer agents.

About this StructureAbout this Structure

1MEJ is a Single protein structure of sequence from Homo sapiens with and as ligands. Active as Phosphoribosylglycinamide formyltransferase, with EC number 2.1.2.2 Full crystallographic information is available from OCA.

ReferenceReference

Crystal structures of human GAR Tfase at low and high pH and with substrate beta-GAR., Zhang Y, Desharnais J, Greasley SE, Beardsley GP, Boger DL, Wilson IA, Biochemistry. 2002 Dec 3;41(48):14206-15. PMID:12450384

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 ==Overview==
-Glycinamide ribonucleotide transformylase (GAR Tfase) is a key, folate-dependent enzyme in the de novo purine biosynthesis pathway and, as, such, has been the target for antitumor drug design. Here, we describe the, crystal structures of the human GAR Tfase (purN) component of the human, trifunctional protein (purD-purM-purN) at various pH values and in complex, with its substrate. Human GAR Tfase exhibits pH-dependent enzyme activity, with its maximum around pH 7.5-8. Comparison of unliganded human GAR Tfase, structures at pH 4.2 and pH 8.5 reveals conformational differences in the, substrate binding loop, which at pH 4.2 occupies the binding cleft and, prohibits substrate binding, while at pH 8.5 is permissive for substrate, binding. The crystal structure of GAR Tfase with its natural substrate, beta-glycinamide ribonucleotide (beta-GAR), at pH 8.5 confirms this, conformational isomerism. Surprisingly, several important structural, differences are found between human GAR Tfase and previously reported E., coli GAR Tfase structures, which have been used as the primary template, for drug design studies. While the E. coli structure gave valuable, insights into the active site and formyl transfer mechanism, differences, in structure and inhibition between the bacterial and mammalian enzymes, suggest that the human GAR Tfase structure is now the appropriate template, for the design of anti-cancer agents.
+Glycinamide ribonucleotide transformylase (GAR Tfase) is a key folate-dependent enzyme in the de novo purine biosynthesis pathway and, as such, has been the target for antitumor drug design. Here, we describe the crystal structures of the human GAR Tfase (purN) component of the human trifunctional protein (purD-purM-purN) at various pH values and in complex with its substrate. Human GAR Tfase exhibits pH-dependent enzyme activity with its maximum around pH 7.5-8. Comparison of unliganded human GAR Tfase structures at pH 4.2 and pH 8.5 reveals conformational differences in the substrate binding loop, which at pH 4.2 occupies the binding cleft and prohibits substrate binding, while at pH 8.5 is permissive for substrate binding. The crystal structure of GAR Tfase with its natural substrate, beta-glycinamide ribonucleotide (beta-GAR), at pH 8.5 confirms this conformational isomerism. Surprisingly, several important structural differences are found between human GAR Tfase and previously reported E. coli GAR Tfase structures, which have been used as the primary template for drug design studies. While the E. coli structure gave valuable insights into the active site and formyl transfer mechanism, differences in structure and inhibition between the bacterial and mammalian enzymes suggest that the human GAR Tfase structure is now the appropriate template for the design of anti-cancer agents.
 ==About this Structure==
@@ Line 14: / Line 14: @@
 [[Category: Phosphoribosylglycinamide formyltransferase]]
 [[Category: Single protein]]
-[[Category: Beardsley, G.P.]]
+[[Category: Beardsley, G P.]]
-[[Category: Boger, D.L.]]
+[[Category: Boger, D L.]]
 [[Category: Desharnais, J.]]
-[[Category: Greasley, S.E.]]
+[[Category: Greasley, S E.]]
-[[Category: Wilson, I.A.]]
+[[Category: Wilson, I A.]]
 [[Category: Zhang, Y.]]
 [[Category: GOL]]
@@ Line 24: / Line 24: @@
 [[Category: purine biosynthesis]]
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri Feb 15 16:23:38 2008''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:54:28 2008''