1vdh
From Proteopedia
(New page: 200px<br /><applet load="1vdh" size="450" color="white" frame="true" align="right" spinBox="true" caption="1vdh, resolution 2.00Å" /> '''Structure-based func...) |
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| - | [[Image:1vdh.gif|left|200px]]<br /><applet load="1vdh" size=" | + | [[Image:1vdh.gif|left|200px]]<br /><applet load="1vdh" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1vdh, resolution 2.00Å" /> | caption="1vdh, resolution 2.00Å" /> | ||
'''Structure-based functional identification of a novel heme-binding protein from thermus thermophilus HB8'''<br /> | '''Structure-based functional identification of a novel heme-binding protein from thermus thermophilus HB8'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The TT1485 gene from Thermus thermophilus HB8 encodes a hypothetical | + | The TT1485 gene from Thermus thermophilus HB8 encodes a hypothetical protein of unknown function with about 20 sequence homologs of bacterial or archaeal origin. Together they form a family of uncharacterized proteins, the cluster of orthologous group COG3253. Using a combination of amino acid sequence analysis, three-dimensional structural studies and biochemical assays, we identified TT1485 as a novel heme-binding protein. The crystal structure reveals that this protein is a pentamer and each monomer exhibits a beta-barrel fold. TT1485 is structurally similar to muconolactone isomerase, but this provided no functional clues. Amino acid sequence analysis revealed remote homology to a heme enzyme, chlorite dismutase. Strikingly, amino acid residues that are highly conserved in the homologous hypothetical proteins and chlorite dismutase cluster around a deep cavity on the surface of each monomer. Molecular modeling shows that the cavity can accommodate a heme group with a strictly conserved His as a heme ligand. TT1485 reconstituted with iron protoporphyrin IX chloride gave a low chlorite dismutase activity, indicating that TT1485 catalyzes a reaction other than chlorite degradation. The presence of a possible Fe-His-Asp triad in the heme proximal site suggests that TT1485 functions as a novel heme peroxidase to detoxify hydrogen peroxide within the cell. |
==About this Structure== | ==About this Structure== | ||
| - | 1VDH is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Thermus_thermophilus Thermus thermophilus]. Full crystallographic information is available from [http:// | + | 1VDH is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Thermus_thermophilus Thermus thermophilus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1VDH OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Masui, R.]] | [[Category: Masui, R.]] | ||
[[Category: Okamoto, A.]] | [[Category: Okamoto, A.]] | ||
| - | [[Category: RSGI, RIKEN | + | [[Category: RSGI, RIKEN Structural Genomics/Proteomics Initiative.]] |
[[Category: Shibata, T.]] | [[Category: Shibata, T.]] | ||
[[Category: Ueyama, N.]] | [[Category: Ueyama, N.]] | ||
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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 15:34:06 2008'' |
Revision as of 13:34, 21 February 2008
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Structure-based functional identification of a novel heme-binding protein from thermus thermophilus HB8
Overview
The TT1485 gene from Thermus thermophilus HB8 encodes a hypothetical protein of unknown function with about 20 sequence homologs of bacterial or archaeal origin. Together they form a family of uncharacterized proteins, the cluster of orthologous group COG3253. Using a combination of amino acid sequence analysis, three-dimensional structural studies and biochemical assays, we identified TT1485 as a novel heme-binding protein. The crystal structure reveals that this protein is a pentamer and each monomer exhibits a beta-barrel fold. TT1485 is structurally similar to muconolactone isomerase, but this provided no functional clues. Amino acid sequence analysis revealed remote homology to a heme enzyme, chlorite dismutase. Strikingly, amino acid residues that are highly conserved in the homologous hypothetical proteins and chlorite dismutase cluster around a deep cavity on the surface of each monomer. Molecular modeling shows that the cavity can accommodate a heme group with a strictly conserved His as a heme ligand. TT1485 reconstituted with iron protoporphyrin IX chloride gave a low chlorite dismutase activity, indicating that TT1485 catalyzes a reaction other than chlorite degradation. The presence of a possible Fe-His-Asp triad in the heme proximal site suggests that TT1485 functions as a novel heme peroxidase to detoxify hydrogen peroxide within the cell.
About this Structure
1VDH is a Protein complex structure of sequences from Thermus thermophilus. Full crystallographic information is available from OCA.
Reference
Structure-based functional identification of a novel heme-binding protein from Thermus thermophilus HB8., Ebihara A, Okamoto A, Kousumi Y, Yamamoto H, Masui R, Ueyama N, Yokoyama S, Kuramitsu S, J Struct Funct Genomics. 2005;6(1):21-32. PMID:15965735
Page seeded by OCA on Thu Feb 21 15:34:06 2008
Categories: Protein complex | Thermus thermophilus | Ebihara, A. | Inoue, Y. | Kousumi, Y. | Kuramitsu, S. | Masui, R. | Okamoto, A. | RSGI, RIKEN Structural Genomics/Proteomics Initiative. | Shibata, T. | Ueyama, N. | Yamamoto, H. | Yokoyama, S. | Beta barrel | Riken structural genomics/proteomics initiative | Rsgi | Structural genomics
