This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.

Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.


1t6k

From Proteopedia

(Difference between revisions)
Jump to: navigation, search
Line 1: Line 1:
-
[[Image:1t6k.jpg|left|200px]]
+
{{Seed}}
 +
[[Image:1t6k.png|left|200px]]
<!--
<!--
Line 9: Line 10:
{{STRUCTURE_1t6k| PDB=1t6k | SCENE= }}
{{STRUCTURE_1t6k| PDB=1t6k | SCENE= }}
-
'''Crystal structure of phzF from Pseudomonas fluorescens 2-79'''
+
===Crystal structure of phzF from Pseudomonas fluorescens 2-79===
-
==Overview==
+
<!--
-
Phenazines, including pyocyanin and iodonin, are biologically active compounds that are believed to confer producing organisms with a competitive growth advantage, and also are thought to be virulence factors in certain diseases including cystic fibrosis. The basic, tricyclic phenazine ring system is synthesized in a series of poorly characterized steps by enzymes encoded in a seven-gene cistron in Pseudomonas and other organisms. Despite the biological importance of these compounds, and our understanding of their mode of action, the biochemistry and mechanisms of phenazine biosynthesis are not well resolved. Here we report the 1.8 A crystal structure of PhzF, a key enzyme in phenazine biosynthesis, solved by molecular replacement. PhzF is structurally similar to the lysine biosynthetic enzyme diaminopimelate epimerase, sharing an unusual fold consisting of two nearly identical domains with the active site located in an occluded cleft between the domains. Unlike diaminopimelate epimerase, PhzF is a dimer in solution. The two apparently independent active sites open toward opposite sides of the dimer and are occupied by sulfate ions in the structure. In vitro experiments using a mixture of purified PhzF, -A, -B, and -G confirm that phenazine-1-carboxylic acid (PCA) is readily produced from trans-2,3-dihydro-3-hydroxyanthranilic acid (DHHA) without aid of other cellular factors. PhzA, -B, and -G have no activity toward DHHA. However, in the presence of PhzF, individually or in combinations, they accelerate the formation of PCA from DHHA and therefore appear to function after the action of PhzF. Surprisingly, PhzF is itself capable of producing PCA, albeit slowly, from DHHA. These observations suggest that PhzF catalyzes the initial step in the conversion of DHHA to PCA, probably via a rearrangement reaction yielding the more reactive 3-oxo analogue of DHHA, and that subsequent steps can occur spontaneously. A hypothetical model for how DHHA binds to the PhzF active site suggests that Glu45 and Asp208 could act as general acid-base catalysts in a rearrangement reaction. Given that four reactions lie between DHHA and PCA, ketone formation, ring formation, decarboxylation, and oxidation, we hypothesize that the similar PhzA and -B proteins catalyze ring formation and thus may be more than noncatalytic accessory proteins. PhzG is almost certainly an oxidase and is predicted to catalyze the final oxidation/aromatization reaction.
+
The line below this paragraph, {{ABSTRACT_PUBMED_15449932}}, adds the Publication Abstract to the page
 +
(as it appears on PubMed at http://www.pubmed.gov), where 15449932 is the PubMed ID number.
 +
-->
 +
{{ABSTRACT_PUBMED_15449932}}
==About this Structure==
==About this Structure==
Line 32: Line 36:
[[Category: Phenazine]]
[[Category: Phenazine]]
[[Category: Phzf]]
[[Category: Phzf]]
-
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 09:35:41 2008''
+
 
 +
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Jul 27 21:52:13 2008''

Revision as of 18:52, 27 July 2008

Image:1t6k.png

Template:STRUCTURE 1t6k

Crystal structure of phzF from Pseudomonas fluorescens 2-79

Template:ABSTRACT PUBMED 15449932

About this Structure

1T6K is a Single protein structure of sequence from Pseudomonas fluorescens. Full crystallographic information is available from OCA.

Reference

Structure and function of the phenazine biosynthesis protein PhzF from Pseudomonas fluorescens 2-79., Parsons JF, Song F, Parsons L, Calabrese K, Eisenstein E, Ladner JE, Biochemistry. 2004 Oct 5;43(39):12427-35. PMID:15449932

Page seeded by OCA on Sun Jul 27 21:52:13 2008

Proteopedia Page Contributors and Editors (what is this?)

OCA

Retrieved from "http://52.214.119.220/wiki/index.php/1t6k"
Personal tools