Three-dimensional structure of a schistosome serpin revealing an unusual configuration of the helical subdomain

Granzin, Joachim; Huang, Ying; Topbaş, Celalettin; Huang, Wen-Ying; Wu, Zhicheng; Misra, Saurav; Hazen, Stanley L.; Blanton, Ronald E.; Lee, Xavier; Weiergräber, Oliver H.

doi:10.1107/s0907444912008372

Cited by 8 publications

(4 citation statements)

References 60 publications

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“…The comparison of the PMSRP1 model with the templates revealed a highly conserved structure at both secondary (three β-sheets and nine α-helices) and three-dimensional levels (RMSD = 1.34 and 0.49 Å, serpin B3 and T. molitor serpin, respectively) (Figures 4 and 6 ). The conservation of the core of the structure reinforced the hypothesis of some authors that the serpin scaffold is intolerant to the deletion of all but peripheral elements of secondary structure [ 61 , 62 ]. Thus changes in non-conserved residues that allowed the folding of the serpin into an active native state were favored by the selective pressure.…”

Section: Resultssupporting

confidence: 59%

“…gambiae (XP_314158) and a slightly lower of 37.8% and 37.4% with the sequences of L. longipalpis (ABV60345) and C. felis (AAN73325), respectively (Figure 4 ). Despite this level of identity, the theoretical prediction of the serpin secondary structure pointed to the conservation of nine α-helices and three β-sheets, similar to other serpin family members [ 61 , 62 ] (Figure 4 ).…”

Section: Resultsmentioning

confidence: 86%

“… Theoretical model of the PMSRP1. A - The structure shows three β-sheets groups (green), nine α-helices (red), the breach (B), shutter (S), gate (G), hinge (H) and the predicted reactive center loop (RCL) regions [ 61 , 62 ]. A 1 shows RCL and the putative residues P17-P9 and P1, P1′, P3′ and P4′ based on alignments.…”

Section: Resultsmentioning

confidence: 99%

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Isolation and molecular characterization of a major hemolymph serpin from the triatomine, Panstrongylus megistus

et al. 2014

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BackgroundChagas disease kills 2.5 thousand people per year of 15 million persons infected in Latin America. The disease is caused by the protozoan, Trypanosome cruzi, and vectored by triatomine insects, including Panstrongylus megistus, an important vector in Brazil. Medicines treating Chagas disease have unpleasant side effects and may be ineffective, therefore, alternative control techniques are required. Knowledge of the T. cruzi interactions with the triatomine host needs extending and new targets/strategies for control identified. Serine and cysteine peptidases play vital roles in protozoan life cycles including invasion and entry of T. cruzi into host cells. Peptidase inhibitors are, therefore, promising targets for disease control.MethodsSDS PAGE and chromatograpy detected and isolated a P. megistus serpin which was peptide sequenced by mass spectrometry. A full amino acid sequence was obtained from the cDNA and compared with other insect serpins. Reverse transcription PCR analysis measured serpin transcripts of P. megistus tissues with and without T. cruzi infection. Serpin homology modeling used the Swiss Model and Swiss-PDB viewer programmes.ResultsThe P. megistus serpin (PMSRP1) has a ca. 40 kDa molecular mass with 404 amino acid residues. A reactive site loop contains a highly conserved hinge region but, based on sequence alignment, the normal cleavage site for serine proteases at P1-P1′ was translocated to the putative position P4′-P5′. A small peptide obtained corresponded to the C-terminal 40 amino acid region. The secondary structure of PMSRP1 indicated nine α-helices and three β-sheets, similar to other serpins. PMSRP1 transcripts occurred in all tested tissues but were highest in the fat body and hemocytes. Levels of mRNA encoding PMSRP1 were significantly modulated in the hemocytes and stomach by T. cruzi infection indicating a role for PMSRP1 in the parasite interactions with P. megistus.ConclusionsFor the first time, a constitutively expressed serpin has been characterized from the hemolymph of a triatomine. This opens up new research avenues into the roles of serine peptidases in the T. cruzi/P. megistus association. Initial experiments indicate a role for PMSRP1 in T. cruzi interactions with P. megistus and will lead to further functional studies of this molecule.

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Section: Resultssupporting

confidence: 59%

Section: Resultsmentioning

confidence: 86%

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Isolation and molecular characterization of a major hemolymph serpin from the triatomine, Panstrongylus megistus

et al. 2014

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“…Data were processed with XIA2/DIALS and assigned to the spacegroup P 3 2 2 1 with a unit cell of a = b = 98.9, c = 115.3 Å, α = β = 90°, γ = 120° [ 23 ]. The structure was solved by molecular replacement using MOLREP [ 24 ] from the CCP4i2 suite, and the structural homolog from Schistosoma haematobium (PDB: 3STO [ 25 ]) with whom it shares 76% sequence identity, as a search model. The model was further manually inspected and built using Coot [ 26 ] and refined using PHENIX.refine [ 27 ].…”

Section: Methodsmentioning

confidence: 99%

Structure, Immunoreactivity, and In Silico Epitope Determination of SmSPI S. mansoni Serpin for Immunodiagnostic Application

et al. 2021

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The human parasitic disease Schistosomiasis is caused by the Schistosoma trematode flatworm that infects freshwaters in tropical regions of the world, particularly in Sub-Saharan Africa, South America, and the Far-East. It has also been observed as an emerging disease in Europe, due to increased immigration. In addition to improved therapeutic strategies, it is imperative to develop novel, rapid, and sensitive diagnostic tests that can detect the Schistosoma parasite, allowing timely treatment. Present diagnosis is difficult and involves microscopy-based detection of Schistosoma eggs in the feces. In this context, we present the 3.22 Å resolution crystal structure of the circulating antigen Serine protease inhibitor from S. mansoni (SmSPI), and we describe it as a potential serodiagnostic marker. Moreover, we identify three potential immunoreactive epitopes using in silico-based epitope mapping methods. Here, we confirm effective immune sera reactivity of the recombinant antigen, suggesting the further investigation of the protein and/or its predicted epitopes as serodiagnostic Schistosomiasis biomarkers.

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Molecular characterization of serine protease inhibitor isoform 3, SmSPI, from Schistosoma mansoni

et al. 2016

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Serine protease inhibitors, known as serpins, are pleiotropic regulators of endogenous and exogenous proteases, and molecule transporters. They have been documented in animals, plants, fungi, bacteria, and viruses; here, we characterize a serpin from the trematode platyhelminth Schistosoma mansoni. At least eight serpins have been found in the genome of S. mansoni, but only two have characterized molecular properties and functions. Here, the function of S. mansoni serpin isoform 3 (SmSPI) was analyzed, using both computational and molecular biological approaches. Phylogenetic analysis showed that SmSPI was closely related to Schistosoma haematobium serpin and Schistosoma japonicum serpin B10. Structure determined in silico confirmed that SmSPI belonged to the serpin superfamily, containing nine α-helices, three β-sheets, and a reactive central loop. SmSPI was highly expressed in schistosomules, predominantly in the head gland, and in adult male and female with intensive accumulation on the spines, which suggests that it may have a role in facilitating intradermal and intravenous survival. Recombinant SmSPI was overexpressed in Escherichia coli; the recombinant protein was of the same size (46 kDa) as the native protein. Immunological analysis suggested that mice infected with S. mansoni responded to rSmSPI at 8 weeks postinfection (wpi) but not earlier. The inhibitory activity of rSmSPI was specific to chymotrypsin but not trypsin, neutrophil elastase, and porcine pancreatic elastase. Elucidating the biological and physiological functions of SmSPI as well as other serpins will lead to further understanding of host-parasite interaction machinery that may provide novel strategies to prevent and control schistosomiasis in the future.

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Three-dimensional structure of a schistosome serpin revealing an unusual configuration of the helical subdomain

Cited by 8 publications

References 60 publications

Isolation and molecular characterization of a major hemolymph serpin from the triatomine, Panstrongylus megistus

Isolation and molecular characterization of a major hemolymph serpin from the triatomine, Panstrongylus megistus

Structure, Immunoreactivity, and In Silico Epitope Determination of SmSPI S. mansoni Serpin for Immunodiagnostic Application

Molecular characterization of serine protease inhibitor isoform 3, SmSPI, from Schistosoma mansoni

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