1t9m
From Proteopedia
(New page: 200px<br /><applet load="1t9m" size="450" color="white" frame="true" align="right" spinBox="true" caption="1t9m, resolution 1.90Å" /> '''X-ray crystal struct...) |
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| - | [[Image:1t9m.jpg|left|200px]]<br /><applet load="1t9m" size=" | + | [[Image:1t9m.jpg|left|200px]]<br /><applet load="1t9m" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1t9m, resolution 1.90Å" /> | caption="1t9m, resolution 1.90Å" /> | ||
'''X-ray crystal structure of phzG from pseudomonas aeruginosa'''<br /> | '''X-ray crystal structure of phzG from pseudomonas aeruginosa'''<br /> | ||
==Overview== | ==Overview== | ||
| - | PhzG is a flavin-dependent oxidase that is believed to play a role in | + | PhzG is a flavin-dependent oxidase that is believed to play a role in phenazine antibiotic synthesis in various bacteria, including Pseudomonas. Phenazines are chorismic acid derivatives that provide the producing organisms, including the opportunistic pathogen P. aeruginosa, with a competitive growth advantage. Here, the crystal structures of PhzG from both P. aeruginosa and P. fluorescens solved in an unliganded state at 1.9 and 1.8 A resolution, respectively, are described. Although the specific reaction in phenazine biosynthesis catalyzed by PhzG is unknown, the structural data indicates that PhzG is closely related to pyridoxine-5'-phosphate oxidase, the Escherichia coli pdxH gene product, which catalyzes the final step in pyridoxal-5'-phosphate (PLP) biosynthesis. A previous proposal suggested that the physiological substrate of PhzG to be 2,3-dihydro-3-hydroxyanthranilic acid (DHHA), a phenazine precursor produced by the sequential actions of the PhzE and PhzD enzymes on chorismate, and that two DHHA molecules dimerized in another enzyme-catalyzed reaction to yield phenazine-1-carboxylate. However, it was not possible to demonstrate any in vitro activity upon incubation of PhzG and DHHA. Interestingly, analysis of the in vitro activities of PhzG in combination with PhzF suggests that PhzF acts on DHHA and that PhzG then reacts with a non-aromatic tricyclic phenazine precusor to catalyze an oxidation/aromatization reaction that yields phenazine-1-carboxylate. It is proposed that phzG arose by duplication of pdxH and that the subtle differences seen between the structures of PhzG and PdxH correlate with the loss of the ability of PhzG to catalyze PLP formation. Sequence alignments and superimpositions of the active sites of PhzG and PdxH reveal that the residues that form a positively charged pocket around the phosphate of PLP in the PdxH-PLP complex are not conserved in PhzG, consistent with the inability of phosphorylated compounds to serve as substrates for PhzG. |
==About this Structure== | ==About this Structure== | ||
| - | 1T9M is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_aeruginosa Pseudomonas aeruginosa] with SO4, FMN and ACY as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1T9M is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_aeruginosa Pseudomonas aeruginosa] with <scene name='pdbligand=SO4:'>SO4</scene>, <scene name='pdbligand=FMN:'>FMN</scene> and <scene name='pdbligand=ACY:'>ACY</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1T9M OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Eisenstein, E.]] | [[Category: Eisenstein, E.]] | ||
| - | [[Category: Ladner, J | + | [[Category: Ladner, J E.]] |
| - | [[Category: Parsons, J | + | [[Category: Parsons, J F.]] |
[[Category: ACY]] | [[Category: ACY]] | ||
[[Category: FMN]] | [[Category: FMN]] | ||
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[[Category: pseudomonas]] | [[Category: pseudomonas]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:11:22 2008'' |
Revision as of 13:11, 21 February 2008
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X-ray crystal structure of phzG from pseudomonas aeruginosa
Overview
PhzG is a flavin-dependent oxidase that is believed to play a role in phenazine antibiotic synthesis in various bacteria, including Pseudomonas. Phenazines are chorismic acid derivatives that provide the producing organisms, including the opportunistic pathogen P. aeruginosa, with a competitive growth advantage. Here, the crystal structures of PhzG from both P. aeruginosa and P. fluorescens solved in an unliganded state at 1.9 and 1.8 A resolution, respectively, are described. Although the specific reaction in phenazine biosynthesis catalyzed by PhzG is unknown, the structural data indicates that PhzG is closely related to pyridoxine-5'-phosphate oxidase, the Escherichia coli pdxH gene product, which catalyzes the final step in pyridoxal-5'-phosphate (PLP) biosynthesis. A previous proposal suggested that the physiological substrate of PhzG to be 2,3-dihydro-3-hydroxyanthranilic acid (DHHA), a phenazine precursor produced by the sequential actions of the PhzE and PhzD enzymes on chorismate, and that two DHHA molecules dimerized in another enzyme-catalyzed reaction to yield phenazine-1-carboxylate. However, it was not possible to demonstrate any in vitro activity upon incubation of PhzG and DHHA. Interestingly, analysis of the in vitro activities of PhzG in combination with PhzF suggests that PhzF acts on DHHA and that PhzG then reacts with a non-aromatic tricyclic phenazine precusor to catalyze an oxidation/aromatization reaction that yields phenazine-1-carboxylate. It is proposed that phzG arose by duplication of pdxH and that the subtle differences seen between the structures of PhzG and PdxH correlate with the loss of the ability of PhzG to catalyze PLP formation. Sequence alignments and superimpositions of the active sites of PhzG and PdxH reveal that the residues that form a positively charged pocket around the phosphate of PLP in the PdxH-PLP complex are not conserved in PhzG, consistent with the inability of phosphorylated compounds to serve as substrates for PhzG.
About this Structure
1T9M is a Single protein structure of sequence from Pseudomonas aeruginosa with , and as ligands. Full crystallographic information is available from OCA.
Reference
Structure of the phenazine biosynthesis enzyme PhzG., Parsons JF, Calabrese K, Eisenstein E, Ladner JE, Acta Crystallogr D Biol Crystallogr. 2004 Nov;60(Pt 11):2110-3. Epub 2004, Oct 20. PMID:15502343
Page seeded by OCA on Thu Feb 21 15:11:22 2008
Categories: Pseudomonas aeruginosa | Single protein | Eisenstein, E. | Ladner, J E. | Parsons, J F. | ACY | FMN | SO4 | Chorismate | Phenazine | Phzg | Pseudomonas
