Ribosomal protein L36 is the smallest protein from the large subunit of the prokaryotic ribosome. It belongs to a family of ribosomal proteins which, on the basis of sequence similarities [1], groups:

• Eubacterial L36.
• Algal and plant chloroplast L36.
• Cyanelle L36.

L36 is a small basic and cysteine-rich protein of 37 amino-acid residues. As a signature pattern, we selected a conserved region that corresponds to positions 11 to 36 in L36 and includes three conserved cysteine residues.