rplL

rplL is a bacterial gene that encodes ribosomal protein L7/L12, a component of the 50S large ribosomal subunit. The protein is small and highly acidic, typically around 120 amino acids in length. In many bacteria, L12 exists as the acetylated form L7 at the N-terminus, reflected in the naming of the two forms.

L7/L12 forms a homodimer and, together with ribosomal protein L10, makes up the L7/L12 stalk of the 50S subunit. This stalk extends from the ribosome surface and plays a key role in translation by interacting with translation factors such as EF-Tu and EF-G, thereby facilitating factor binding and GTP hydrolysis during protein synthesis. The L12 dimer is flexible and contributes to the ribosome’s adaptability during different stages of translation.

Genetically, rplL is typically part of the operon containing other ribosomal protein genes and is often highly conserved across bacterial species. The gene is generally essential for efficient ribosome function; loss or disruption of rplL often results in severe growth defects due to impaired protein synthesis. Because L7/L12 is among the most abundant ribosomal proteins, its expression level is tightly coordinated with overall ribosome biogenesis and cellular growth.

Conservation and significance: L7/L12 is one of the most conserved and abundant components of bacterial ribosomes, and sequence variation in rplL is frequently used in comparative and evolutionary studies of bacteria. The protein’s role in recruiting and coordinating translation factors makes it central to the ribosome’s catalytic cycle, contributing to the efficiency and regulation of protein synthesis.