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Comparative analysis of cystatin superfamily in platyhelminths.

Guo A - PLoS ONE (2015)

Bottom Line: However, it is noteworthy that cestode cystatins had two tandem repeated domains, although the second tandem repeated domain did not contain a cystatin-like domain, which has not been previously reported.Although no conserved disulfide bond was found in T. solium cystatin, the models of T. solium cystatin and chicken cystatin corresponded at the site of the first disulfide bridge of the chicken cystatin.The same results were obtained for other cestode cystatins.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Disease, Yangzhou, Jiangsu, China.

ABSTRACT
The cystatin superfamily is comprised of cysteine proteinase inhibitors and encompasses at least 3 subfamilies: stefins, cystatins and kininogens. In this study, the platyhelminth cystatin superfamily was identified and grouped into stefin and cystatin subfamilies. The conserved domain of stefins (G, QxVxG) was observed in all members of platyhelminth stefins. The three characteristics of cystatins, the cystatin-like domain (G, QxVxG, PW), a signal peptide, and one or two conserved disulfide bonds, were observed in platyhelminths, with the exception of cestodes, which lacked the conserved disulfide bond. However, it is noteworthy that cestode cystatins had two tandem repeated domains, although the second tandem repeated domain did not contain a cystatin-like domain, which has not been previously reported. Tertiary structure analysis of Taenia solium cystatin, one of the cestode cystatins, demonstrated that the N-terminus of T. solium cystatin formed a five turn α-helix, a five stranded β-pleated sheet and a hydrophobic edge, similar to the structure of chicken cystatin. Although no conserved disulfide bond was found in T. solium cystatin, the models of T. solium cystatin and chicken cystatin corresponded at the site of the first disulfide bridge of the chicken cystatin. However, the two models were not similar regarding the location of the second disulfide bridge of chicken cystatin. These results showed that T. solium cystatin and chicken cystatin had similarities and differences, suggesting that the biochemistry of T. solium cystatin could be similar to chicken cystatin in its inhibitory function and that it may have further functional roles. The same results were obtained for other cestode cystatins. Phylogenetic analysis showed that cestode cystatins constituted an independent clade and implied that cestode cystatins should be considered to have formed a new clade during evolution.

No MeSH data available.


Related in: MedlinePlus

Alignment of cystatin superfamily domain.The domain was aligned using ClustalW and adjusted manually. (A) The three parts of the papain binding domain (G, QXVXG, PW) are displayed. Signal peptides and disulfide bridges are shown. The N-terminal amino acid extention of Tas_stefin2 is shaded pale grey. The number of amino acids of each protein is shown at last of sequence. (B) The tandem repeated domain of cestode cystatins is shown. The first amino acid and the last amino acid in the tandem repeated domain is numbered outside of them.
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pone.0124683.g002: Alignment of cystatin superfamily domain.The domain was aligned using ClustalW and adjusted manually. (A) The three parts of the papain binding domain (G, QXVXG, PW) are displayed. Signal peptides and disulfide bridges are shown. The N-terminal amino acid extention of Tas_stefin2 is shaded pale grey. The number of amino acids of each protein is shown at last of sequence. (B) The tandem repeated domain of cestode cystatins is shown. The first amino acid and the last amino acid in the tandem repeated domain is numbered outside of them.

Mentions: Cystatin superfamily members were identified in platyhelminths and are shown in Table 2. One stefin and one cystatin were characterized in each of T. solium and T. saginata, whereas one cystatin and two stefins were found in the T. asiatica genome. The expression of the stefins and the cystatins in the above mentioned three species was then confirmed by PCR using their corresponding cDNA as template (Fig 1). Similarly, the putative cystatin superfamily members were also identified in other platyhelminth species (Table 2). A single stefin gene was identified in each of E. multilocularis, E. granulosus, S. japonicum, S. mansoni and S. mediterranea. In addition, a single cystatin gene was found in each genome of tree cestodes including E. multilocularis, E. granulosus and H. microstoma, while two cystatin genes were found in each of S. japonicum and S. mediterranea. Furthermore, three different spliced cystatin proteins were deduced from electronic annotation in S. mansoni (Smp_034420.1, Smp_034420.2 and Smp_034420.3) (Figs 2A and S2). According to analysis of the transcriptomic and genomic data, two ancestral lineages, stefins and cystatins, were present in numerous platyhelminths. This result was in agreement with studies in some eukaryotic species with two ancestral lineages [40], but in disagreement with the early proposition that stefins, cystatins and kininogens appear almost simultaneously [41].


Comparative analysis of cystatin superfamily in platyhelminths.

Guo A - PLoS ONE (2015)

Alignment of cystatin superfamily domain.The domain was aligned using ClustalW and adjusted manually. (A) The three parts of the papain binding domain (G, QXVXG, PW) are displayed. Signal peptides and disulfide bridges are shown. The N-terminal amino acid extention of Tas_stefin2 is shaded pale grey. The number of amino acids of each protein is shown at last of sequence. (B) The tandem repeated domain of cestode cystatins is shown. The first amino acid and the last amino acid in the tandem repeated domain is numbered outside of them.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4390278&req=5

pone.0124683.g002: Alignment of cystatin superfamily domain.The domain was aligned using ClustalW and adjusted manually. (A) The three parts of the papain binding domain (G, QXVXG, PW) are displayed. Signal peptides and disulfide bridges are shown. The N-terminal amino acid extention of Tas_stefin2 is shaded pale grey. The number of amino acids of each protein is shown at last of sequence. (B) The tandem repeated domain of cestode cystatins is shown. The first amino acid and the last amino acid in the tandem repeated domain is numbered outside of them.
Mentions: Cystatin superfamily members were identified in platyhelminths and are shown in Table 2. One stefin and one cystatin were characterized in each of T. solium and T. saginata, whereas one cystatin and two stefins were found in the T. asiatica genome. The expression of the stefins and the cystatins in the above mentioned three species was then confirmed by PCR using their corresponding cDNA as template (Fig 1). Similarly, the putative cystatin superfamily members were also identified in other platyhelminth species (Table 2). A single stefin gene was identified in each of E. multilocularis, E. granulosus, S. japonicum, S. mansoni and S. mediterranea. In addition, a single cystatin gene was found in each genome of tree cestodes including E. multilocularis, E. granulosus and H. microstoma, while two cystatin genes were found in each of S. japonicum and S. mediterranea. Furthermore, three different spliced cystatin proteins were deduced from electronic annotation in S. mansoni (Smp_034420.1, Smp_034420.2 and Smp_034420.3) (Figs 2A and S2). According to analysis of the transcriptomic and genomic data, two ancestral lineages, stefins and cystatins, were present in numerous platyhelminths. This result was in agreement with studies in some eukaryotic species with two ancestral lineages [40], but in disagreement with the early proposition that stefins, cystatins and kininogens appear almost simultaneously [41].

Bottom Line: However, it is noteworthy that cestode cystatins had two tandem repeated domains, although the second tandem repeated domain did not contain a cystatin-like domain, which has not been previously reported.Although no conserved disulfide bond was found in T. solium cystatin, the models of T. solium cystatin and chicken cystatin corresponded at the site of the first disulfide bridge of the chicken cystatin.The same results were obtained for other cestode cystatins.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Veterinary Etiological Biology, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Disease, Yangzhou, Jiangsu, China.

ABSTRACT
The cystatin superfamily is comprised of cysteine proteinase inhibitors and encompasses at least 3 subfamilies: stefins, cystatins and kininogens. In this study, the platyhelminth cystatin superfamily was identified and grouped into stefin and cystatin subfamilies. The conserved domain of stefins (G, QxVxG) was observed in all members of platyhelminth stefins. The three characteristics of cystatins, the cystatin-like domain (G, QxVxG, PW), a signal peptide, and one or two conserved disulfide bonds, were observed in platyhelminths, with the exception of cestodes, which lacked the conserved disulfide bond. However, it is noteworthy that cestode cystatins had two tandem repeated domains, although the second tandem repeated domain did not contain a cystatin-like domain, which has not been previously reported. Tertiary structure analysis of Taenia solium cystatin, one of the cestode cystatins, demonstrated that the N-terminus of T. solium cystatin formed a five turn α-helix, a five stranded β-pleated sheet and a hydrophobic edge, similar to the structure of chicken cystatin. Although no conserved disulfide bond was found in T. solium cystatin, the models of T. solium cystatin and chicken cystatin corresponded at the site of the first disulfide bridge of the chicken cystatin. However, the two models were not similar regarding the location of the second disulfide bridge of chicken cystatin. These results showed that T. solium cystatin and chicken cystatin had similarities and differences, suggesting that the biochemistry of T. solium cystatin could be similar to chicken cystatin in its inhibitory function and that it may have further functional roles. The same results were obtained for other cestode cystatins. Phylogenetic analysis showed that cestode cystatins constituted an independent clade and implied that cestode cystatins should be considered to have formed a new clade during evolution.

No MeSH data available.


Related in: MedlinePlus