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

Following purification by affinity chromatography, a Leishmania major S-hex ylglutathione- binding protein of molecular mass 66 kDa was isolated. The i mmune 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 tr ansformation effector homologue, namely ribosomal protein S3a, and thus was named LmS3a-related protein (LmS3arp). A 1027 bp cDNA fragment was found t o contain the entire parasite gene encoding for a highly basic protein of 3 0 kDa calculated molecular mass sharing homology to various ribosomal S3a p roteins from different species. Using computer methods for a multiple align ment and sequence motif search, we found that LmS3arp shares a sequence hom ology to class theta glutathione S-transferase mainly in a segment containi ng critical residues involved in glutathione binding. These new findings ar e discussed in the light of recent published data showing multiple function (s) of the ribosomal proteins S3a. (C) 1999 Elsevier Science B.V. All right s reserved.