J. Biol. Chem., Vol. 263, Issue 14, 6538-6546, May, 1988
Primary structure of the archaebacterial Methanococcus vannielii ribosomal protein L12. Amino acid sequence determination, oligonucleotide hybridization, and sequencing of the gene
O Strobel, AK Kopke, RM Kamp, A Bock and B Wittmann-Liebold
Max-Planck-Institut fur Molekulare Genetik, Abteilung Wittmann, Berlin, West Germany.
The primary structure of ribosomal protein L12 from Methanococcus vannielii
has been determined by direct amino acid sequence analysis with automated
liquid phase Edman degradation of the entire protein and manual
4-N,N'-dimethylaminoazobenzene-4'- isothiocyanate/phenylisothiocyanate
sequencing of fragments obtained by enzymatic digestion and by partial acid
hydrolysis. The knowledge of the amino acid sequences of these various
fragments allowed the synthesis of two oligonucleotide probes complementary
to the 5'- and the 3'-end of the gene, and they were used for hybridization
with digested M. vannielii chromosomal DNA. Both oligonucleotide probes
gave similar and clear hybridization signals. The plasmid pMvaX1 containing
the entire gene of protein L12 was obtained. The nucleotide sequence
complemented the partial amino acid sequence, and it is in full agreement
with the protein sequence and the amino acid analysis. Comparison of
secondary structural elements and hydrophobicity plots of the M. vannielii
protein L12 with the known L12 sequences derived from other archaebacterial
and eukaryotic sources show strong homologies among these sequences. They
contain an exceptional highly conserved hydrophilic sequence area in the
C-terminal part of the proteins. In comparison with eubacterial L12
proteins, the conservation is reduced to single amino acid residues.
However, the eubacterial L12 proteins have hydrophilic regions similar to
those of L12 from M. vannielii. These regions are predicted to be located
at the surface of the proteins, as has been proven to be the case in
crystallized Escherichia coli L12 protein. It is possible that the strongly
conserved hydrophilic sequence regions form part of the factor-binding
domain.