Cloning and characterization of Giardia intestinalis cyclophilin

The cyclophilins (Cyps) are family members of proteins that exhibit peptidylprolyl cis-trans isomerase (PPIase, EC 5.2.1.8) activity and bind the immunosuppressive agent cyclosprin A (CsA) in varying degrees. During the process of random sequencing of a cDNA library made from Giardia intestinalis WB strain, the cyclophilin gene (gicyp 1) was isolated. An open reading frame of gicyp 1 gene was 576 nucleotides, which corresponded to a translation product of 176 amino acids (Gicyp 1). The identity with other Cyps was about 58-71%. The 13 residues that constituted the CsA binding site of human cyclophilin were also detected in the amino acid sequence of Gicyp 1, including tryptophan residue essential for the drug binding. The single copy of the gicyp 1 gene was detected in the G. intestinalis chromosome by southern hybridization analysis. Recombinant Gicyp 1 protein clearly accelerated the rate of cis--

Separación de proteínas del disco ventral de Giardia intestinalis / Separation of proteins from the ventral disk of Giardia intestinalis

Mediante separación isoeléctrica y reisoelectroenfoque se obtuvieron las proteínas de citoesqueleto de Giardia intestinalis con características de giardinas y tubulinas, constituyentes principales del disco ventral. El peso molecular fue 30 a 45 kDa así como las de sus variantes determinadas por la diferencia de pH. Además de las mismas se obtuvieron predominantemente polipéptidos de peso molecular de 97 y 115 kDa. Por inmunocitoquímica se demostró que estas proteínas de peso molecular elevado se localizaron sobre la membrana del trofozoíto, y en menor proporción se observaron proteínas con pesos moleculares semejantes a los de giardinas y tubulinas