Crystal Structure of the Complex of Brugia malayi Cyclophilin and Cyclosporin A † , ‡
Stanford Synchrotron Radiation Laboratory, SLAC, P.O. Box 4249, Bin 69, Stanford University, Stanford, California 94309, USA. Biochemistry
(Impact Factor: 3.02).
02/2000; 39(3):592-8. DOI: 10.1021/bi991730q
The resistance of the human parasite Brugia malayi to the antiparasitic activity of cyclosporin A (CsA) may arise from the presence of cyclophilins with relatively low affinity for the drug. The structure of the complex of B. malayi cyclophilin (BmCYP-1) and CsA, with eight independent copies in the asymmetric unit, has been determined at a resolution of 2.7 A. The low affinity of BmCYP-1 for CsA arises from incomplete preorganization of the binding site so that the formation of a hydrogen bond between His132 of BmCYP-1 and N-methylleucine 9 of CsA is associated with a shift in the backbone of approximately 1 A in this region.
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ABSTRACT: A highly diversified member of the cyclophilin family of peptidyl-prolyl cis-trans isomerases has been isolated from the human parasite Onchocerca volvulus(OvCYP-16). This 25-kDa cyclophilin shares 43–46% similarity to other filarial cyclophilins but does not belong to any of the
groups previously defined in invertebrates or vertebrates. A homolog was also isolated from Caenorhabditis elegans(CeCYP-16). Both recombinant O. volvulus and C. elegans cyclophilins were found to possess an enzyme activity with similar substrate preference and insensitivity to cyclosporin
A. They represent novel cyclophilins with important differences in the composition of the drug-binding site in particular,
namely, a Glu124 (C. elegans) or Asp123 (O. volvulus) residue present in a critical position. Site-directed mutagenesis studies and kinetic characterization demonstrated that
the single residue dictates the degree of binding to substrate and cyclosporin A.CeCYP-16::GFP-expressing lines were generated with expression in the anterior and posterior distal portions of the intestine,
in all larval stages and adults. An exception was found in the dauer stage, where fluorescence was observed in both the cell
bodies and processes of the ventral chord motor neurons but was absent from the intestine. These studies highlight the extensive
diversification of cyclophilins in an important human parasite and a closely related model organism.
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ABSTRACT: Cyclophilins are enzymes catalyzing the cis-trans isomerization of peptidyl-prolyl bonds and belong to the enzyme class of peptidyl-prolyl cis-trans isomerases (PPIases), which includes two more families (FK506 binding proteins and parvulins). We report the characterization of a novel cyclophilin (Moca-cyp) isolated from Drosophila melanogaster. The single-copy Moca-cyp gene, which is localized on chromosome 3R, was cloned and sequenced. The sequence alignment of the gene against Moca-cyp cDNA allowed us to define its intron/exon structure and to identify a variant cDNA corresponding to an alternatively spliced mRNA. By embryo in situ RNA hybridization and immunostaining, we show that the expression of Moca-cyp is regulated during embryogenesis of Drosophila. The 120-kDa nuclear Moca-cyp protein belongs to a subfamily of large cyclophilins sharing structural and enzymatic features: their highly conserved N-terminal PPIase domain is extended by a positively charged and divergent C-terminal tail. Compared with cyclophilin 18, the enzymatic activity carried by the PPIase domain of Moca-cyp is low, exhibits characteristic substrate specificity, and shows a reduced sensitivity to the drug cyclosporin A (CsA). The reduced affinity for CsA is one of the typical features linking members of this subfamily and is probably the consequence of two amino acid substitutions within their active site. Another structural feature shared by members of this subfamily is a conserved polypeptidic segment ("moca" domain) that we report for the first time. The moca domain is located within the C-terminal tail and is the exclusive hallmark of a group of large cyclophilins found in multicellular organisms of the animal kingdom.
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ABSTRACT: Cyclophilins are a family of proteins found ubiquitously in eukaryotes, many of which bind to the immunosuppressive drug cyclosporin A (CsA). CsA has been found to have anti-parasitic effects against a variety of helminth and protozoan parasites and this activity could be mediated via cyclophilin. In this study we characterize a full length cyclophilin gene from Echinococcus granulosus, the associated natural gene and expression pattern, and investigate the functional properties of the recombinant E. granulosus cyclophilin protein. In addition, the effects of CsA were investigated on E. granulosus protoscoleces in in vitro culture. The full length E. granulosus cyclophilin cDNA encodes a protein of 20 kDa and is encoded by a single gene (EGCyP-1) comprising 2 exons separated by a 31 bp intron. The gene is expressed constitutively in all E. granulosus life-cycle stages examined. Recombinant E. granulosus cyclophilin (egCyP-l) exhibited functional enzyme activity as an isomerase. Treatment of in vitro cultures of E. granulosus protoscoleces with CsA was found to be lethal to the parasites. No protoscoleces survived treatment with 10 microg/ml of CsA over 7 culture days, as determined by observing motility and the uptake of toluidine blue dye. Untreated protoscoleces remained viable for the duration of experiments. The survival of protoscoleces was CsA dose dependent. A concentration of 10 microg/ml CsA was 100% lethal while doses of 8 microg/ml and 5 microg/ml resulted in 82% and 32% killing, respectively, after 7 days in culture. The anti-parasitic activity of CsA may have the potential to be developed as a new therapeutic agent for treatment of cystic hydatidosis in humans.
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