Synthesis and soluble pools of ribosomal proteins in Rhodopseudomonas palustris

Abstract

The specific antibodies prepared against two purified ribosomal proteins (19 and 24) and total 66-S ribosomal proteins have been utilized to measure free ribosomal proteins in Rhodopseudomonas palustris. The free ribosomal protein pool (66 S) amounts to 1–2% of the total soluble proteins of R. palustris. In addition, the size of free ribosomal protein pool (66 S) is calculated to be approx. 7% of the total ribosomal protein on the mature 66-S ribosomes from the pulse-labelling data. A study of the pool size indicates that ribosomal proteins are synthesized at a constant rate during exponential growth. However, during abnormal conditions such as antibiotic treatment, individual ribosomal proteins behave in a manner distinct from the average behavior of total 66-S ribosomal proteins. The co-ordination in the biosynthesis of free ribosomal proteins is no longer apparent during chloramphenicol treatment. Measurements on the free ribosomal protein pools following physiological stress treatment indicate that duing the recovery period, rate of ribosome assembly is greater than the rate of ribosomal protein synthesis.