Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Target Concepts:
Gene/Protein
Disease
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Drug
Enzyme
Compound
Query: UNIPROT:P04040 (
Catalase
)
3,577
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Catalase
is one of the key antioxidant enzymes and it appears to be involved in protection against immune infection and oxidative stress. Here, two catalase cDNAs (ChCat-1 and ChCat-2) were isolated from hemocytes of Crassostrea hongkongensis using SSH and RACE. The full-length cDNAs of ChCat-1 and ChCat-2 are 1913 and 2466 bp in length, encoding proteins of 515 and 511 amino acids, respectively. Multiple alignments of amino acid sequences revealed that both ChCat-1 and ChCat-2 possess several characteristic features of the catalase family of enzymes, including one proximal active site signature, one heme-ligand signature, and three catalytic amino acid residues (His(72), Asn(145) and Tyr(355)). Phylogenetic analysis indicates that these two catalases may share a common ancestral gene and result from a gene duplication event following the divergence of bivalves and gastropods. Constitutive expression of ChCat-1 and ChCat-2 was observed in all tissues studied, with highest levels of expression in gill and muscle, respectively. The expression of both genes was inducible by
bacterial infection
, and reached the maximum at 8 h (9.0-fold) and 12 h (2.3-fold) post-infection, respectively. Furthermore, both the purified ChCat-1 and ChCat-2 protein displayed a strong catalase activity, and S2 cells carrying ChCat-1 or ChCat-2 showed a higher degree of resistance to H(2)O(2) than that of control cells. In a word, this is the first report of the presence of two catalase genes in a single marine bivalve, and our results highlight the involvement of both ChCat-1 and ChCat-2 in host protection against pathogen infection and oxidative stress in C. hongkongensis.
...
PMID:Two catalase homologs are involved in host protection against bacterial infection and oxidative stress in Crassostrea hongkongensis. 2187 67
During the translation process, transfer RNA (tRNA) carries amino acids to ribosomes for protein synthesis. Each codon of mRNA is recognized by a specific tRNA, and enzyme-catalysed modifications to tRNA regulate translation. TtcA is a unique tRNA-thiolating enzyme that requires an iron-sulfur ([Fe-S]) cluster to catalyse thiolation of tRNA. In this study, the physiological functions of a putative ttcA in Pseudomonas aeruginosa, an opportunistic human pathogen that causes serious problems in hospitals, were characterized. A P. aeruginosa ttcA-deleted mutant was constructed, and mutant cells were rendered hypersensitive to oxidative stress, such as hydrogen peroxide (H
2
O
2
) treatment.
Catalase
activity was lower in the ttcA mutant, suggesting that this gene plays a role in protecting against oxidative stress. Moreover, the ttcA mutant demonstrated attenuated virulence in a Drosophila melanogaster host model. Site-directed mutagenesis analysis revealed that the conserved cysteine motifs involved in [Fe-S] cluster ligation were required for TtcA function. Furthermore, ttcA expression increased upon H
2
O
2
exposure, implying that enzyme levels are induced under stress conditions. Overall, the data suggest that P. aeruginosa ttcA plays a critical role in protecting against oxidative stress via catalase activity and is required for successful
bacterial infection
of the host.
...
PMID:Pseudomonas aeruginosa ttcA encoding tRNA-thiolating protein requires an iron-sulfur cluster to participate in hydrogen peroxide-mediated stress protection and pathogenicity. 3008 77
