Forms part of the ribosomal stalk which helps the ribosome interact with GTP-bound translation factors. Is thus essential for accurate translation. Homodimer. Part of the ribosomal stalk of the 50S ribosomal subunit. Forms a multimeric L10(L12)X complex, where L10 forms an elongated spine to which 2 to 4 L12 dimers bind in a sequential fashion. Binds GTP-bound translation factors. Acetylation of Met-1 converts MA1 to MA2. Belongs to the bacterial ribosomal protein bL12 family.