1gso
From Proteopedia
(New page: 200px<br /><applet load="1gso" size="450" color="white" frame="true" align="right" spinBox="true" caption="1gso, resolution 1.6Å" /> '''GLYCINAMIDE RIBONUCLE...) |
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| - | [[Image:1gso.gif|left|200px]]<br /><applet load="1gso" size=" | + | [[Image:1gso.gif|left|200px]]<br /><applet load="1gso" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1gso, resolution 1.6Å" /> | caption="1gso, resolution 1.6Å" /> | ||
'''GLYCINAMIDE RIBONUCLEOTIDE SYNTHETASE (GAR-SYN) FROM E. COLI.'''<br /> | '''GLYCINAMIDE RIBONUCLEOTIDE SYNTHETASE (GAR-SYN) FROM E. COLI.'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Glycinamide ribonucleotide synthetase (GAR-syn) catalyzes the second step | + | Glycinamide ribonucleotide synthetase (GAR-syn) catalyzes the second step of the de novo purine biosynthetic pathway; the conversion of phosphoribosylamine, glycine, and ATP to glycinamide ribonucleotide (GAR), ADP, and Pi. GAR-syn containing an N-terminal polyhistidine tag was expressed as the SeMet incorporated protein for crystallographic studies. In addition, the protein as isolated contains a Pro294Leu mutation. This protein was crystallized, and the structure solved using multiple-wavelength anomalous diffraction (MAD) phase determination and refined to 1.6 A resolution. GAR-syn adopts an alpha/beta structure that consists of four domains labeled N, A, B, and C. The N, A, and C domains are clustered to form a large central core structure whereas the smaller B domain is extended outward. Two hinge regions, which might readily facilitate interdomain movement, connect the B domain and the main core. A search of structural databases showed that the structure of GAR-syn is similar to D-alanine:D-alanine ligase, biotin carboxylase, and glutathione synthetase, despite low sequence similarity. These four enzymes all utilize similar ATP-dependent catalytic mechanisms even though they catalyze different chemical reactions. Another ATP-binding enzyme with low sequence similarity but unknown function, synapsin Ia, was also found to share high structural similarity with GAR-syn. Interestingly, the GAR-syn N domain shows similarity to the N-terminal region of glycinamide ribonucleotide transformylase and several dinucleotide-dependent dehydrogenases. Models of ADP and GAR binding were generated based on structure and sequence homology. On the basis of these models, the active site lies in a cleft between the large domain and the extended B domain. Most of the residues that facilitate ATP binding belong to the A or B domains. The N and C domains appear to be largely responsible for substrate specificity. The structure of GAR-syn allows modeling studies of possible channeling complexes with PPRP amidotransferase. |
==About this Structure== | ==About this Structure== | ||
| - | 1GSO is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Active as [http://en.wikipedia.org/wiki/Phosphoribosylamine--glycine_ligase Phosphoribosylamine--glycine ligase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=6.3.4.13 6.3.4.13] Full crystallographic information is available from [http:// | + | 1GSO is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Active as [http://en.wikipedia.org/wiki/Phosphoribosylamine--glycine_ligase Phosphoribosylamine--glycine ligase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=6.3.4.13 6.3.4.13] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GSO OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Phosphoribosylamine--glycine ligase]] | [[Category: Phosphoribosylamine--glycine ligase]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Ealick, S | + | [[Category: Ealick, S E.]] |
| - | [[Category: Kappock, T | + | [[Category: Kappock, T J.]] |
[[Category: Stubbe, J.]] | [[Category: Stubbe, J.]] | ||
[[Category: Wang, W.]] | [[Category: Wang, W.]] | ||
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[[Category: substrate channeling]] | [[Category: substrate channeling]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:53:31 2008'' |
Revision as of 10:53, 21 February 2008
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GLYCINAMIDE RIBONUCLEOTIDE SYNTHETASE (GAR-SYN) FROM E. COLI.
Overview
Glycinamide ribonucleotide synthetase (GAR-syn) catalyzes the second step of the de novo purine biosynthetic pathway; the conversion of phosphoribosylamine, glycine, and ATP to glycinamide ribonucleotide (GAR), ADP, and Pi. GAR-syn containing an N-terminal polyhistidine tag was expressed as the SeMet incorporated protein for crystallographic studies. In addition, the protein as isolated contains a Pro294Leu mutation. This protein was crystallized, and the structure solved using multiple-wavelength anomalous diffraction (MAD) phase determination and refined to 1.6 A resolution. GAR-syn adopts an alpha/beta structure that consists of four domains labeled N, A, B, and C. The N, A, and C domains are clustered to form a large central core structure whereas the smaller B domain is extended outward. Two hinge regions, which might readily facilitate interdomain movement, connect the B domain and the main core. A search of structural databases showed that the structure of GAR-syn is similar to D-alanine:D-alanine ligase, biotin carboxylase, and glutathione synthetase, despite low sequence similarity. These four enzymes all utilize similar ATP-dependent catalytic mechanisms even though they catalyze different chemical reactions. Another ATP-binding enzyme with low sequence similarity but unknown function, synapsin Ia, was also found to share high structural similarity with GAR-syn. Interestingly, the GAR-syn N domain shows similarity to the N-terminal region of glycinamide ribonucleotide transformylase and several dinucleotide-dependent dehydrogenases. Models of ADP and GAR binding were generated based on structure and sequence homology. On the basis of these models, the active site lies in a cleft between the large domain and the extended B domain. Most of the residues that facilitate ATP binding belong to the A or B domains. The N and C domains appear to be largely responsible for substrate specificity. The structure of GAR-syn allows modeling studies of possible channeling complexes with PPRP amidotransferase.
About this Structure
1GSO is a Single protein structure of sequence from Escherichia coli. Active as Phosphoribosylamine--glycine ligase, with EC number 6.3.4.13 Full crystallographic information is available from OCA.
Reference
X-ray crystal structure of glycinamide ribonucleotide synthetase from Escherichia coli., Wang W, Kappock TJ, Stubbe J, Ealick SE, Biochemistry. 1998 Nov 10;37(45):15647-62. PMID:9843369
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