Ribosomal protein S8 is one of the proteins from the small ribosomal subunit. In Escherichia coli, S8 is known to bind directly to 16S ribosomal RNA. It belongs to a family of ribosomal proteins which, on the basis of sequence similarities [1], groups:

• Eubacterial S8.
• Algal and plant chloroplast S8.
• Cyanelle S8.
• Archaebacterial S8.
• Marchantia polymorpha mitochondrial S8.
• Mammalian S15A.
• Plant S15A.
• Yeast S22 (S24).

As a signature pattern, we selected the best conserved region located in the C-terminal section of these proteins.