2fps
From Proteopedia
(New page: 200px<br /><applet load="2fps" size="450" color="white" frame="true" align="right" spinBox="true" caption="2fps, resolution 2.20Å" /> '''Crystal structure of...) |
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| - | [[Image:2fps.jpg|left|200px]]<br /><applet load="2fps" size=" | + | [[Image:2fps.jpg|left|200px]]<br /><applet load="2fps" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="2fps, resolution 2.20Å" /> | caption="2fps, resolution 2.20Å" /> | ||
'''Crystal structure of the N-terminal domain of E.coli HisB- Apo Ca model.'''<br /> | '''Crystal structure of the N-terminal domain of E.coli HisB- Apo Ca model.'''<br /> | ||
==Overview== | ==Overview== | ||
| - | HisB from Escherichia coli is a bifunctional enzyme catalyzing the sixth | + | HisB from Escherichia coli is a bifunctional enzyme catalyzing the sixth and eighth steps of l-histidine biosynthesis. The N-terminal domain (HisB-N) possesses histidinol phosphate phosphatase activity, and its crystal structure shows a single domain with fold similarity to the haloacid dehalogenase (HAD) enzyme family. HisB-N forms dimers in the crystal and in solution. The structure shows the presence of a structural Zn(2+) ion stabilizing the conformation of an extended loop. Two metal binding sites were also identified in the active site. Their presence was further confirmed by isothermal titration calorimetry. HisB-N is active in the presence of Mg(2+), Mn(2+), Co(2+), or Zn(2+), but Ca(2+) has an inhibitory effect. We have determined structures of several intermediate states corresponding to snapshots along the reaction pathway, including that of the phosphoaspartate intermediate. A catalytic mechanism, different from that described for other HAD enzymes, is proposed requiring the presence of the second metal ion not found in the active sites of previously characterized HAD enzymes, to complete the second half-reaction. The proposed mechanism is reminiscent of two-Mg(2+) ion catalysis utilized by DNA and RNA polymerases and many nucleases. The structure also provides an explanation for the inhibitory effect of Ca(2+). |
==About this Structure== | ==About this Structure== | ||
| - | 2FPS 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 ZN, CA and CL as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Histidinol-phosphatase Histidinol-phosphatase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.3.15 3.1.3.15] Full crystallographic information is available from [http:// | + | 2FPS 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 <scene name='pdbligand=ZN:'>ZN</scene>, <scene name='pdbligand=CA:'>CA</scene> and <scene name='pdbligand=CL:'>CL</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Histidinol-phosphatase Histidinol-phosphatase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.3.15 3.1.3.15] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2FPS OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Histidinol-phosphatase]] | [[Category: Histidinol-phosphatase]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: BSGI, Montreal-Kingston | + | [[Category: BSGI, Montreal-Kingston Bacterial Structural Genomics Initiative.]] |
[[Category: Cygler, M.]] | [[Category: Cygler, M.]] | ||
[[Category: Matte, A.]] | [[Category: Matte, A.]] | ||
| - | [[Category: Rangarajan, E | + | [[Category: Rangarajan, E S]] |
[[Category: CA]] | [[Category: CA]] | ||
[[Category: CL]] | [[Category: CL]] | ||
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[[Category: structural genomics]] | [[Category: structural genomics]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 17:23:54 2008'' |
Revision as of 15:23, 21 February 2008
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Crystal structure of the N-terminal domain of E.coli HisB- Apo Ca model.
Overview
HisB from Escherichia coli is a bifunctional enzyme catalyzing the sixth and eighth steps of l-histidine biosynthesis. The N-terminal domain (HisB-N) possesses histidinol phosphate phosphatase activity, and its crystal structure shows a single domain with fold similarity to the haloacid dehalogenase (HAD) enzyme family. HisB-N forms dimers in the crystal and in solution. The structure shows the presence of a structural Zn(2+) ion stabilizing the conformation of an extended loop. Two metal binding sites were also identified in the active site. Their presence was further confirmed by isothermal titration calorimetry. HisB-N is active in the presence of Mg(2+), Mn(2+), Co(2+), or Zn(2+), but Ca(2+) has an inhibitory effect. We have determined structures of several intermediate states corresponding to snapshots along the reaction pathway, including that of the phosphoaspartate intermediate. A catalytic mechanism, different from that described for other HAD enzymes, is proposed requiring the presence of the second metal ion not found in the active sites of previously characterized HAD enzymes, to complete the second half-reaction. The proposed mechanism is reminiscent of two-Mg(2+) ion catalysis utilized by DNA and RNA polymerases and many nucleases. The structure also provides an explanation for the inhibitory effect of Ca(2+).
About this Structure
2FPS is a Single protein structure of sequence from Escherichia coli with , and as ligands. Active as Histidinol-phosphatase, with EC number 3.1.3.15 Full crystallographic information is available from OCA.
Reference
Structural snapshots of Escherichia coli histidinol phosphate phosphatase along the reaction pathway., Rangarajan ES, Proteau A, Wagner J, Hung MN, Matte A, Cygler M, J Biol Chem. 2006 Dec 8;281(49):37930-41. Epub 2006 Sep 11. PMID:16966333
Page seeded by OCA on Thu Feb 21 17:23:54 2008
Categories: Escherichia coli | Histidinol-phosphatase | Single protein | BSGI, Montreal-Kingston Bacterial Structural Genomics Initiative. | Cygler, M. | Matte, A. | Rangarajan, E S | CA | CL | ZN | Bacterial structure genomics | Bifunctional enzyme. | Bsgi | Hisb | Histidinol phosphate phosphatase | Montreal-kingston bacterial structural genomics initiative | Structural genomics
