Complete amino acid sequences of the ribosomal proteins L25, L29 and L31 from the archaebacterium Halobacterium marismortui

Abstract

Ribosomal proteins were extracted from 50s ribosomal subunits of the archaebacterium Halobacterium marismortui by decreasing the concentration of Mg2+ and K', and the proteins were separated and purified by ion-exchange column chromatography on DEAE-cellulose. Ten proteins were purified to homogeneity and three of these proteins were subjected to sequence analysis. The complete amino acid sequences of the ribosomal proteins L25, L29 and L31 were established by analyses of the peptides obtained by enzymatic digestion with trypsin, Staphylococcus aureus protease, chymotrypsin and lysylendopeptidase. Proteins L25, L29 and L31 consist of 84, 115 and 95 amino acid residues with the molecular masses of 9472 Da, 12293 Da and 10418 Da respectively. A comparison of their sequences with those of other large-ribosomal-subunit proteins from other organisms revealed that protein L25 from H. marismortui is homologous to protein L23 from Escherichia coli (34.6%), Bacillus stearothermophilus (41 .So/,), and tobacco chloroplasts (16.3%) as well as to protein L25 from yeast (38.0%). Proteins L29 and L31 do not appear to be homologous to any other ribosomal proteins whose structures are so far known.In previous papers [l -41 we have reported the complete amino acid sequences of a number of proteins from 30s ribosomal subunits from the archaebacterium Halobacterium marismortui. The rationale of this ongoing investigation is not only to examine the evolutionary origin of the halobacterial ribosomal proteins, but also to evaluate the amino acid changes which have allowed the adaptation into a high-salt environment. A comparison of homologous proteins from distantly related organisms also provides useful information about functionally and/or structurally important sites, since important regions are expected to be conserved through evolution.In addition to our primary structural analyses, studies on the spatial structure of H. marismortui ribosomal proteins [ S ] and intact ribosomal subunits [6] are now in progress at our institute. In particular, Makowski et al.[7] have performed X-ray diffraction studies on crystals of the large ribosomal subunits from H. marismortui which diffract to 0.6-nm resolution.As a part of this investigation on the structure of the halobacterial ribosomal proteins and also to facilitate the structural analysis on crystals of the intact large ribosomal subunits from H. marisrplortui, we are now extending the sequence analyses to the proteins of the 50s ribosomal subunit from this halophilic bacterium. At present, a number of 50s-ribosomal-subunit proteins have been purified by ion-exchange chromatography for sequence analysis (unpublished results). In this paper we describe the isolation and complete amino acid sequences of ribosomal proteins L25, L29 and L31 from H. marismortui and present their relationship with other ribosomal proteins whose primary structures have been determined.

Amino acid sequences of ribosomal proteins S11 from Bacillus stearothermophilus and S19 from Halobacterium marismortui Comparison of the ribosomal protein S11 family

“…Based on this comparison, the evolutionary tree for the ribosomal protein Sll family ( fig.3) has two main branches: one for eubacterial and chloroplast Sl 1, and another for halophilic and eukaryotic proteins. This relationship is consistent with previous results derived from the comparisons of other ribosomal protein families [4,22,23]. Similar results to those presented in fig.3 have recently been obtained from sequence analyses of ribosomal proteins from the archaebacterium Methanococcus vannielii.…”

Primary structures of five ribosomal proteins from the archaebacterium Halobacterium marismortui and their structural relationships to eubacterial and eukaryotic ribosomal proteins

“…mari,vnortui ribosomal proteins S6, S12, S15, L16, L29 and L31. which have previously been sequenced [S, 6,81.…”

“…For instance, this is true for H . marisnzortui proteins S14, S16, S19 and L2S [4,6,71. On the other hand, H. marismortui protein L9 exhibited a slightly higher similarity to eubacterial B. stearothermophilus protein L15 than to eukaryotic yeast protein L29 from yeast.…”

Resolution power of two‐dimensional electrophoresis and identification of proteins from gels

“…In contrast to other species, the ribosomal proteins of halophilic archaea are in general acidic. The 2-DE technique described by Hatakeyama and Kimura [20] was used to separate the proteins of 30s ribosomal subunits of H. marismortui (Fig. 2).…”