Cloning of a Leishmania major gene encoding for an antigen with extensive homology to ribosomal protein S3a

Abstract

Following purification by affinity chromatography, a Leishmania major S-hexylglutathione- binding protein of molecular mass 66 kDa was isolated. The immune serum against the parasite 66 kDa polypeptide when used to screen a L. major cDNA library could identify clones encoding for the human v-fos transformation effector homologue, namely ribosomal protein S3a, and thus was named LmS3a-related protein (LmS3arp). A 1027 bp cDNA fragment was found to contain the entire parasite gene encoding for a highly basic protein of 30 kDa calculated molecular mass sharing homology to various ribosomal S3a proteins from different species. Using computer methods for a multiple alignment and sequence motif search, we found that LmS3arp shares a sequence homology to class theta glutathione S-transferase mainly in a segment containing critical residues involved in glutathione binding. These new findings are discussed in the light of recent published data showing multiple function(s) of the ribosomal proteins S3a. (C) 1999 Elsevier Science B.V. All rights reserved.