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SmCL3, a Gastrodermal Cysteine Protease of the Human Blood Fluke Schistosoma mansoni

BACKGROUND: Blood flukes of the genus Schistosoma are platyhelminth parasites that infect 200 million people worldwide. Digestion of nutrients from the host bloodstream is essential for parasite development and reproduction. A network of proteolytic enzymes (proteases) facilitates hydrolysis of host...

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Autores principales: Dvořák, Jan, Mashiyama, Susan T., Sajid, Mohammed, Braschi, Simon, Delcroix, Melaine, Schneider, Eric L., McKerrow, Wilson H., Bahgat, Mahmoud, Hansell, Elizabeth, Babbitt, Patricia C., Craik, Charles S., McKerrow, James H., Caffrey, Conor R.
Formato: Texto
Lenguaje:English
Publicado: Public Library of Science 2009
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2685030/
https://www.ncbi.nlm.nih.gov/pubmed/19488406
http://dx.doi.org/10.1371/journal.pntd.0000449
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author Dvořák, Jan
Mashiyama, Susan T.
Sajid, Mohammed
Braschi, Simon
Delcroix, Melaine
Schneider, Eric L.
McKerrow, Wilson H.
Bahgat, Mahmoud
Hansell, Elizabeth
Babbitt, Patricia C.
Craik, Charles S.
McKerrow, James H.
Caffrey, Conor R.
author_facet Dvořák, Jan
Mashiyama, Susan T.
Sajid, Mohammed
Braschi, Simon
Delcroix, Melaine
Schneider, Eric L.
McKerrow, Wilson H.
Bahgat, Mahmoud
Hansell, Elizabeth
Babbitt, Patricia C.
Craik, Charles S.
McKerrow, James H.
Caffrey, Conor R.
author_sort Dvořák, Jan
collection PubMed
description BACKGROUND: Blood flukes of the genus Schistosoma are platyhelminth parasites that infect 200 million people worldwide. Digestion of nutrients from the host bloodstream is essential for parasite development and reproduction. A network of proteolytic enzymes (proteases) facilitates hydrolysis of host hemoglobin and serum proteins. METHODOLOGY/PRINCIPAL FINDINGS: We identified a new cathepsin L termed SmCL3 using PCR strategies based on S. mansoni EST sequence data. An ortholog is present in Schistosoma japonicum. SmCL3 was heterologously expressed as an active enzyme in the yeast, Pichia pastoris. Recombinant SmCL3 has a broad pH activity range against peptidyl substrates and is inhibited by Clan CA protease inhibitors. Consistent with a function in degrading host proteins, SmCL3 hydrolyzes serum albumin and hemoglobin, is localized to the adult gastrodermis, and is expressed mainly in those life stages infecting the mammalian host. The predominant form of SmCL3 in the parasite exists as a zymogen, which is unusual for proteases. This zymogen includes an unusually long prodomain with alpha helical secondary structure motifs. The striking specificity of SmCL3 for amino acids with large aromatic side chains (Trp and Tyr) at the P2 substrate position, as determined with positional scanning-synthetic combinatorial library, is consistent with a molecular model that shows a large and deep S2 pocket. A sequence similarity network (SSN) view clusters SmCL3 and other cathepsins L in accordance with previous large-scale phylogenetic analyses that identify six super kingdoms. CONCLUSIONS/SIGNIFICANCE: SmCL3 is a gut-associated cathepsin L that may contribute to the network of proteases involved in degrading host blood proteins as nutrients. Furthermore, this enzyme exhibits some unusual sequence and biophysical features that may result in additional functions. The visualization of network inter-relationships among cathepsins L suggests that these enzymes are suitable ‘marker sequences’ for inclusion in future phylogenetic analyses.
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spelling pubmed-26850302009-06-02 SmCL3, a Gastrodermal Cysteine Protease of the Human Blood Fluke Schistosoma mansoni Dvořák, Jan Mashiyama, Susan T. Sajid, Mohammed Braschi, Simon Delcroix, Melaine Schneider, Eric L. McKerrow, Wilson H. Bahgat, Mahmoud Hansell, Elizabeth Babbitt, Patricia C. Craik, Charles S. McKerrow, James H. Caffrey, Conor R. PLoS Negl Trop Dis Research Article BACKGROUND: Blood flukes of the genus Schistosoma are platyhelminth parasites that infect 200 million people worldwide. Digestion of nutrients from the host bloodstream is essential for parasite development and reproduction. A network of proteolytic enzymes (proteases) facilitates hydrolysis of host hemoglobin and serum proteins. METHODOLOGY/PRINCIPAL FINDINGS: We identified a new cathepsin L termed SmCL3 using PCR strategies based on S. mansoni EST sequence data. An ortholog is present in Schistosoma japonicum. SmCL3 was heterologously expressed as an active enzyme in the yeast, Pichia pastoris. Recombinant SmCL3 has a broad pH activity range against peptidyl substrates and is inhibited by Clan CA protease inhibitors. Consistent with a function in degrading host proteins, SmCL3 hydrolyzes serum albumin and hemoglobin, is localized to the adult gastrodermis, and is expressed mainly in those life stages infecting the mammalian host. The predominant form of SmCL3 in the parasite exists as a zymogen, which is unusual for proteases. This zymogen includes an unusually long prodomain with alpha helical secondary structure motifs. The striking specificity of SmCL3 for amino acids with large aromatic side chains (Trp and Tyr) at the P2 substrate position, as determined with positional scanning-synthetic combinatorial library, is consistent with a molecular model that shows a large and deep S2 pocket. A sequence similarity network (SSN) view clusters SmCL3 and other cathepsins L in accordance with previous large-scale phylogenetic analyses that identify six super kingdoms. CONCLUSIONS/SIGNIFICANCE: SmCL3 is a gut-associated cathepsin L that may contribute to the network of proteases involved in degrading host blood proteins as nutrients. Furthermore, this enzyme exhibits some unusual sequence and biophysical features that may result in additional functions. The visualization of network inter-relationships among cathepsins L suggests that these enzymes are suitable ‘marker sequences’ for inclusion in future phylogenetic analyses. Public Library of Science 2009-06-02 /pmc/articles/PMC2685030/ /pubmed/19488406 http://dx.doi.org/10.1371/journal.pntd.0000449 Text en Dvořák et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Dvořák, Jan
Mashiyama, Susan T.
Sajid, Mohammed
Braschi, Simon
Delcroix, Melaine
Schneider, Eric L.
McKerrow, Wilson H.
Bahgat, Mahmoud
Hansell, Elizabeth
Babbitt, Patricia C.
Craik, Charles S.
McKerrow, James H.
Caffrey, Conor R.
SmCL3, a Gastrodermal Cysteine Protease of the Human Blood Fluke Schistosoma mansoni
title SmCL3, a Gastrodermal Cysteine Protease of the Human Blood Fluke Schistosoma mansoni
title_full SmCL3, a Gastrodermal Cysteine Protease of the Human Blood Fluke Schistosoma mansoni
title_fullStr SmCL3, a Gastrodermal Cysteine Protease of the Human Blood Fluke Schistosoma mansoni
title_full_unstemmed SmCL3, a Gastrodermal Cysteine Protease of the Human Blood Fluke Schistosoma mansoni
title_short SmCL3, a Gastrodermal Cysteine Protease of the Human Blood Fluke Schistosoma mansoni
title_sort smcl3, a gastrodermal cysteine protease of the human blood fluke schistosoma mansoni
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2685030/
https://www.ncbi.nlm.nih.gov/pubmed/19488406
http://dx.doi.org/10.1371/journal.pntd.0000449
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