Cloning and characterization of a selenium-independent glutathione peroxidase (HC29) from adultHaemonchus contortus

Abstract

The complete coding sequence of Haemonchus (H.) contortus HC29 cDNA was generated by rapid amplification of cDNA ends in combination with PCR using primers targeting the 5'- and 3'-ends of the partial mRNA sequence. The cloned HC29 cDNA was shown to be 1,113 bp in size with an open reading frame of 507 bp, encoding a protein of 168 amino acid with a calculated molecular mass of 18.9 kDa. Amino acid sequence analysis revealed that the cloned HC29 cDNA contained the conserved catalytic triad and dimer interface of selenium-independent glutathione peroxidase (GPX). Alignment of the predicted amino acid sequences demonstrated that the protein shared 44.7~80.4% similarity with GPX homologues in the thioredoxin-like family. Phylogenetic analysis revealed close evolutionary proximity of the GPX sequence to the counterpart sequences. These results suggest that HC29 cDNA is a GPX, a member of the thioredoxin-like family. Alignment of the nucleic acid and amino acid sequences of HC29 with those of the reported selenium-independent GPX of H. contortus showed that HC29 contained different types of spliced leader sequences as well as dimer interface sites, although the active sites of both were identical. Enzymatic analysis of recombinant prokaryotic HC29 protein showed activity for the hydrolysis of H2O2. These findings indicate that HC29 is a selenium-independent GPX of H. contortus.

A glutathione peroxidase from Antarctic psychrotrophic bacteriumPseudoalteromonassp. ANT506: Cloning and heterologous expression of the gene and characterization of recombinant enzyme

“…The K m assay of rPsGPx demonstrated that it could catalyze H 2 O 2 in the presence of GSH, which further proved that rPsGPx was a GPx of the thioredoxin-like family. 19 As compared with other reported GPxs from different organisms, rPsGPx exhibits some distinct enzymatic properties. For example, rPsGPx manifested the highest activity at 30 C and retained at least 40% activity even at 0 C (Fig.…”

“…18 In this study, rPsGPx contained three active site residues (Cys 72 , Gln 103 , and Trp 154 ), and the amino acid residues were conserved in all other members and were vital for active-site structure. 17,19,20 Meanwhile, the GPx from adult Haemonchus contortus possessed active site residues Cys 38 , Gln 73 , and Trp 127 , 19 whereas the GPx from halotolerant Chlamydomonas sp. W80 contained amino acid residues Cys 37 , Gln 71 , and Trp 125 .…”

Modulation of the Functions of Goat Peripheral Blood Mononuclear Cells by Fasciola gigantica Thioredoxin Peroxidase In Vitro

“…F. gigantica -derived ESPs, identified in the present study (rFgTPx) and in previous studies (rFg14-3-3e [ 20 ] and rFgRab10 [ 21 ]), have induced Th1 (IFN-γ, IL-2) and Th2 (IL-4, IL-10, TGF-β) cytokines, except IL-4 and IFN-γ, whose levels were low in response to rFg14-3-3e. Cytokines are produced by a variety of immune cells and play various roles in protecting the host and maintaining tissue homeostasis [ 28 , 29 ]. In an earlier study on F. gigantica infection in buffaloes, we observed that a mixed Th1/Th2 immune response is dominant from 28 to 70 dpi, to promote F. gigantica survival while limiting host tissue damage [ 27 ].…”

Characterization of biochemical properties of a selenium-independent glutathione peroxidase ofCryptosporidium parvum

“…One of the major functional differences between Se-GPxs and NS-GPxs is that Se-GPxs catalyse the reduction of both organic and inorganic peroxides like H 2 O 2 , whereas NS-GPxs react preferentially with organic peroxides (Tang et al 1995;Sun et al 2012). One of the major functional differences between Se-GPxs and NS-GPxs is that Se-GPxs catalyse the reduction of both organic and inorganic peroxides like H 2 O 2 , whereas NS-GPxs react preferentially with organic peroxides (Tang et al 1995;Sun et al 2012).…”