1d7a: Difference between revisions
No edit summary |
No edit summary |
||
| Line 1: | Line 1: | ||
[[Image:1d7a.jpg|left|200px]] | [[Image:1d7a.jpg|left|200px]] | ||
<!-- | |||
The line below this paragraph, containing "STRUCTURE_1d7a", creates the "Structure Box" on the page. | |||
You may change the PDB parameter (which sets the PDB file loaded into the applet) | |||
or the SCENE parameter (which sets the initial scene displayed when the page is loaded), | |||
or leave the SCENE parameter empty for the default display. | |||
| | --> | ||
| | {{STRUCTURE_1d7a| PDB=1d7a | SCENE= }} | ||
}} | |||
'''CRYSTAL STRUCTURE OF E. COLI PURE-MONONUCLEOTIDE COMPLEX.''' | '''CRYSTAL STRUCTURE OF E. COLI PURE-MONONUCLEOTIDE COMPLEX.''' | ||
| Line 30: | Line 27: | ||
[[Category: Mathews, I I.]] | [[Category: Mathews, I I.]] | ||
[[Category: Stubbe, J.]] | [[Category: Stubbe, J.]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 13:31:33 2008'' | |||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | |||
Revision as of 13:31, 2 May 2008
CRYSTAL STRUCTURE OF E. COLI PURE-MONONUCLEOTIDE COMPLEX.
OverviewOverview
BACKGROUND: Conversion of 5-aminoimidazole ribonucleotide (AIR) to 4-carboxyaminoimidazole ribonucleotide (CAIR) in Escherichia coli requires two proteins - PurK and PurE. PurE has recently been shown to be a mutase that catalyzes the unusual rearrangement of N(5)-carboxyaminoimidazole ribonucleotide (N(5)-CAIR), the PurK reaction product, to CAIR. PurEs from higher eukaryotes are homologous to E. coli PurE, but use AIR and CO(2) as substrates to produce CAIR directly. RESULTS: The 1.50 A crystal structure of PurE reveals an octameric structure with 422 symmetry. A central three-layer (alphabetaalpha) sandwich domain and a kinked C-terminal helix form the folded structure of the monomeric unit. The structure reveals a cleft at the interface of two subunits and near the C-terminal helix of a third subunit. Co-crystallization experiments with CAIR confirm this to be the mononucleotide-binding site. The nucleotide is bound predominantly to one subunit, with conserved residues from a second subunit making up one wall of the cleft. CONCLUSIONS: The crystal structure of PurE reveals a unique quaternary structure that confirms the octameric nature of the enzyme. An analysis of the native crystal structure, in conjunction with sequence alignments and studies of co-crystals of PurE with CAIR, reveals the location of the active site. The environment of the active site and the analysis of conserved residues between the two classes of PurEs suggests a model for the differences in their substrate specificities and the relationship between their mechanisms.
About this StructureAbout this Structure
1D7A is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of Escherichia coli PurE, an unusual mutase in the purine biosynthetic pathway., Mathews II, Kappock TJ, Stubbe J, Ealick SE, Structure. 1999 Nov 15;7(11):1395-406. PMID:10574791 Page seeded by OCA on Fri May 2 13:31:33 2008