Analysis of kethoxal bound to ribosomal proteins from Escherichia coli 70S reacted ribosomes

To investigate ribosome topography and possible function, 70S ribosomes of $\text{Escherichia coli}$ were reacted with the dicarbonyl compound kethoxal. Ribosomal protein was extracted after reaction, and through two dimensional gel electrophoresis, the reactive proteins of the two subunits were identified. From the 30S subunit, the most reacted proteins were S2, S3, S4, S5 and S7 and from the 50S subunit, L1, L5, L16, L17, L18 and L27. The results with kethoxal are compared with other modifiers of ribosomal proteins.