2iyn
From Proteopedia
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==Overview== | ==Overview== | ||
| - | PhoB is an Escherichia coli transcription factor from a two-component, signal transduction system that is sensitive to limiting environmental, phosphate conditions. It consists of an N-terminal receiver domain (RD), and a C-terminal DNA-binding domain. The protein is activated upon, phosphorylation at the RD, an event that depends on Mg(2+) binding. The, structure of PhoB RD in complex with Mg(2+) is presented, which shows, three protomers in the asymmetric unit that interact across two different, surfaces. One association is symmetric and has been described as a, non-active dimerization contact; the other involves the, alpha4-beta5-alpha5 interface and recalls the contact found in activated, PhoB. However, here this last interaction is not perfectly symmetric and, helix alpha4, which in ... | + | PhoB is an Escherichia coli transcription factor from a two-component, signal transduction system that is sensitive to limiting environmental, phosphate conditions. It consists of an N-terminal receiver domain (RD), and a C-terminal DNA-binding domain. The protein is activated upon, phosphorylation at the RD, an event that depends on Mg(2+) binding. The, structure of PhoB RD in complex with Mg(2+) is presented, which shows, three protomers in the asymmetric unit that interact across two different, surfaces. One association is symmetric and has been described as a, non-active dimerization contact; the other involves the, alpha4-beta5-alpha5 interface and recalls the contact found in activated, PhoB. However, here this last interaction is not perfectly symmetric and, helix alpha4, which in the activated molecule undergoes a helical shift, becomes strongly destabilized in one of the interacting monomers. All, protomers bind the cation in a similar manner but, interestingly, at the, prospective binding site for the phosphate moiety the side chains of, either Glu88 (in helix alpha4) or Trp54 alternate and interact with, active-site atoms. When Glu88 is inside the cavity, helix alpha4 is, arranged similarly to the unliganded wild-type structure. However, if, Trp54 is present, the helix loses its contacts with the active-site cavity, and vanishes. Accordingly, the presence of Trp54 in the active site, induces a flexible state in helix alpha4, potentially allowing a helical, shift that phosphorylation would eventually stabilize. |
==About this Structure== | ==About this Structure== | ||
| - | 2IYN is a | + | 2IYN is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with MG as [http://en.wikipedia.org/wiki/ligand ligand]. Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2IYN OCA]. |
==Reference== | ==Reference== | ||
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[[Category: two-component regulatory system]] | [[Category: two-component regulatory system]] | ||
| - | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 14:14:49 2007'' |
Revision as of 12:09, 5 November 2007
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THE CO-FACTOR-INDUCED PRE-ACTIVE CONFORMATION IN PHOB
Overview
PhoB is an Escherichia coli transcription factor from a two-component, signal transduction system that is sensitive to limiting environmental, phosphate conditions. It consists of an N-terminal receiver domain (RD), and a C-terminal DNA-binding domain. The protein is activated upon, phosphorylation at the RD, an event that depends on Mg(2+) binding. The, structure of PhoB RD in complex with Mg(2+) is presented, which shows, three protomers in the asymmetric unit that interact across two different, surfaces. One association is symmetric and has been described as a, non-active dimerization contact; the other involves the, alpha4-beta5-alpha5 interface and recalls the contact found in activated, PhoB. However, here this last interaction is not perfectly symmetric and, helix alpha4, which in the activated molecule undergoes a helical shift, becomes strongly destabilized in one of the interacting monomers. All, protomers bind the cation in a similar manner but, interestingly, at the, prospective binding site for the phosphate moiety the side chains of, either Glu88 (in helix alpha4) or Trp54 alternate and interact with, active-site atoms. When Glu88 is inside the cavity, helix alpha4 is, arranged similarly to the unliganded wild-type structure. However, if, Trp54 is present, the helix loses its contacts with the active-site cavity, and vanishes. Accordingly, the presence of Trp54 in the active site, induces a flexible state in helix alpha4, potentially allowing a helical, shift that phosphorylation would eventually stabilize.
About this Structure
2IYN is a Single protein structure of sequence from Escherichia coli with MG as ligand. Structure known Active Site: AC1. Full crystallographic information is available from OCA.
Reference
The cofactor-induced pre-active conformation in PhoB., Sola M, Drew DL, Blanco AG, Gomis-Ruth FX, Coll M, Acta Crystallogr D Biol Crystallogr. 2006 Sep;62(Pt 9):1046-57. Epub 2006, Aug 19. PMID:16929106
Page seeded by OCA on Mon Nov 5 14:14:49 2007
Categories: Escherichia coli | Single protein | Blanco, A.G. | Coll, M. | Drew, D.L. | Gomis-Ruth, F.X. | Sola, M. | MG | Activation of the pho regulon | Activator | Alpha/beta doubly wound fold | Dna- binding | Dna-binding | Gene regulation | Phosphate regulation | Phosphate transport | Phosphorylation | Sensory transduction | Transcription | Transcription factor | Transcription regulation | Transport | Two-component regulatory system
