Analysis of the genomic sequence encoding the 29-kDa cysteine-rich protein of Entamoeba histolytica.

By analyzing cDNA and genomic clones coding for the 29-kDa cysteine-rich protein of Entamoeba histolytica, substantial sequence differences were found to the 5'-end of a previously described full-length cDNA coding for the same protein (Reed et al., 1992), which was reported to contain an untranslated 5'-sequence of at least 171 nucleotides, unusual for E. histolytica cDNAs. We found evidence that the cDNA published by Reed et al. (1992) represents a hybridclone composed of two unrelated sequences and that the gene coding for the 29-kDa molecule comprises all of the features typical for E. histolytica genes. A data base analysis revealed substantial sequence homology of the 29-kDa protein to a class of polypeptides found in prokaryotic organisms that may be involved in the inactivation of hydrogen peroxide.