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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.


Phylogenetic analysis (A) and architecture (B) of platyhelminth cystatin superfamily.(A) Phylogenetic tree derived from the alignment of complete predicted proteins sequences. Nodes with confidence values greater than 60% are indicated based on maximum likelihood (ML). Subfamilies are indicated at the right. (B) The fragment from Gly (G) to Cys (C) or Pro-Trp (PW) residue represent predicted cystatin-like domain. The RPT represent tandem repeated domains. Disulfide bonds between conserved cysteines are denoted. The typical motifs for Stefin (human stefin A) and cystatin (chicken cystatin) subfamily members are represented on top and below, respectively. The first three letters: (Egr) E. granulosus; (Emu) E. multilocularis; (Sja) S. japonicum; (Sma) S. mansoni; (Sme) S. mediterranea; (Tas) T. asiatica; (Tsa) T. saginata; (Tso) T. solium; (Hmi) H. microstoma; (Cel) C. Elegans.
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pone.0124683.g003: Phylogenetic analysis (A) and architecture (B) of platyhelminth cystatin superfamily.(A) Phylogenetic tree derived from the alignment of complete predicted proteins sequences. Nodes with confidence values greater than 60% are indicated based on maximum likelihood (ML). Subfamilies are indicated at the right. (B) The fragment from Gly (G) to Cys (C) or Pro-Trp (PW) residue represent predicted cystatin-like domain. The RPT represent tandem repeated domains. Disulfide bonds between conserved cysteines are denoted. The typical motifs for Stefin (human stefin A) and cystatin (chicken cystatin) subfamily members are represented on top and below, respectively. The first three letters: (Egr) E. granulosus; (Emu) E. multilocularis; (Sja) S. japonicum; (Sma) S. mansoni; (Sme) S. mediterranea; (Tas) T. asiatica; (Tsa) T. saginata; (Tso) T. solium; (Hmi) H. microstoma; (Cel) C. Elegans.

Mentions: The phylogenetic tree of the platyhelminth cystatin superfamily was constructed and is shown in Fig 3A. Although S. japonicum cystatin1 was annotated to have a cystatin-like domain, no signal peptide and cystatin-like domain was predicted using SMART. Thus, it was discarded when the tree was constructed. For S. mansoni, one of three splicing forms of cystatin, with an intact cystatin-like domain was chosen to construct the tree. The phylogenetic analysis clearly showed that the members of platyhelminth cystatin superfamily were divided into two independent groups, the stefin and cystatin subfamilies. The stefins in trematodes, nematodes and cestodes branched together in a clade discrete from the planarian one. All platyhelminth species had a single copy for the stefin except for T. asiatica with two stefins (stefin1 and stefin2). All stefin genes in T. solium, T. saginata and T. asiatica (cestodes) were confirmed by PCR using their respective cDNA as template (Fig 1). The results showed that two stefin genes, stefin 1 and stefin 2, were really expressed in T. asiatica (Table 2) and provided evidence to rule out the possibility of incorrect genome assembly. The phylogenetic analysis showed that T. asiatica stefin1 was closely related to T. solium stefin, and T. asiatica stefin2 to T. saginata stefin. The results of the genomic organization and the phylogenetic analysis supported the idea that T. asiatica stefin2 may have arisen during evolution before the separation of these cestode parasites.


Comparative analysis of cystatin superfamily in platyhelminths.

Guo A - PLoS ONE (2015)

Phylogenetic analysis (A) and architecture (B) of platyhelminth cystatin superfamily.(A) Phylogenetic tree derived from the alignment of complete predicted proteins sequences. Nodes with confidence values greater than 60% are indicated based on maximum likelihood (ML). Subfamilies are indicated at the right. (B) The fragment from Gly (G) to Cys (C) or Pro-Trp (PW) residue represent predicted cystatin-like domain. The RPT represent tandem repeated domains. Disulfide bonds between conserved cysteines are denoted. The typical motifs for Stefin (human stefin A) and cystatin (chicken cystatin) subfamily members are represented on top and below, respectively. The first three letters: (Egr) E. granulosus; (Emu) E. multilocularis; (Sja) S. japonicum; (Sma) S. mansoni; (Sme) S. mediterranea; (Tas) T. asiatica; (Tsa) T. saginata; (Tso) T. solium; (Hmi) H. microstoma; (Cel) C. Elegans.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4390278&req=5

pone.0124683.g003: Phylogenetic analysis (A) and architecture (B) of platyhelminth cystatin superfamily.(A) Phylogenetic tree derived from the alignment of complete predicted proteins sequences. Nodes with confidence values greater than 60% are indicated based on maximum likelihood (ML). Subfamilies are indicated at the right. (B) The fragment from Gly (G) to Cys (C) or Pro-Trp (PW) residue represent predicted cystatin-like domain. The RPT represent tandem repeated domains. Disulfide bonds between conserved cysteines are denoted. The typical motifs for Stefin (human stefin A) and cystatin (chicken cystatin) subfamily members are represented on top and below, respectively. The first three letters: (Egr) E. granulosus; (Emu) E. multilocularis; (Sja) S. japonicum; (Sma) S. mansoni; (Sme) S. mediterranea; (Tas) T. asiatica; (Tsa) T. saginata; (Tso) T. solium; (Hmi) H. microstoma; (Cel) C. Elegans.
Mentions: The phylogenetic tree of the platyhelminth cystatin superfamily was constructed and is shown in Fig 3A. Although S. japonicum cystatin1 was annotated to have a cystatin-like domain, no signal peptide and cystatin-like domain was predicted using SMART. Thus, it was discarded when the tree was constructed. For S. mansoni, one of three splicing forms of cystatin, with an intact cystatin-like domain was chosen to construct the tree. The phylogenetic analysis clearly showed that the members of platyhelminth cystatin superfamily were divided into two independent groups, the stefin and cystatin subfamilies. The stefins in trematodes, nematodes and cestodes branched together in a clade discrete from the planarian one. All platyhelminth species had a single copy for the stefin except for T. asiatica with two stefins (stefin1 and stefin2). All stefin genes in T. solium, T. saginata and T. asiatica (cestodes) were confirmed by PCR using their respective cDNA as template (Fig 1). The results showed that two stefin genes, stefin 1 and stefin 2, were really expressed in T. asiatica (Table 2) and provided evidence to rule out the possibility of incorrect genome assembly. The phylogenetic analysis showed that T. asiatica stefin1 was closely related to T. solium stefin, and T. asiatica stefin2 to T. saginata stefin. The results of the genomic organization and the phylogenetic analysis supported the idea that T. asiatica stefin2 may have arisen during evolution before the separation of these cestode parasites.

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.