Cartography of ribosomal proteins of the 30s subunit from the halophilic Haloarcula marismortui and complete sequence analysis of protein HS26

By two-dimensional polyacrylamide gel electrophoresis of 30S ribosomal subunit proteins (S proteins) from Haloarcula marismortui we identified 27 distinct spots and analyzed all of them by protein sequence analysis. We demonstrated that protein HmaS2 (HS2) is encoded by the open reading frame orfMSG and has sequence similarities to the S2 ribosomal protein family. The proteins HmaS5 and HmaS14 were identified as spots HS7 and HS21/HS22, respectively. Protein HS4 was characterized by amino-terminal sequence analysis. The spot HS25 was recognized as an individual protein and also characterized by sequence analysis. Furthermore, the complete primary sequence of HS26 is reported, showing similarity only to eukaryotic ribosomal proteins. The sequence data of a further basic protein shows a high degree of similarity to ribosomal protein S12, therefore it was designated HmaS12. Slightly different results compared to published sequence data were obtained for the proteins HS12 and HmaS19. The putative ‘ribosomal’ protein HSH could not be localized in the two-dimensional pattern of the total 30S ribosomal subunit proteins of H. marismortui. Therefore, it seems to be unlikely that this protein is a real constituent of the H. marismortui ribosome.