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.
1vdh
From Proteopedia
|
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 Wed Nov 21 04:36:10 2007
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
