Fraction of total protein that is ribosomal protein (αr)

Range 0.09-0.22 Table - link unitless
Organism Bacteria Escherichia coli
Reference Bremer, H., Dennis, P. P. (1996) Modulation of chemical composition and other parameters of the cell by growth rate. Neidhardt, et al. eds. Escherichia coli and Salmonella typhimurium: Cellular and Molecular Biology, 2nd ed. chapter 97 Table 1
Primary Source Dennis PP, Bremer H. Differential rate of ribosomal protein synthesis in Escherichia coli B/r. J Mol Biol. 1974 Apr 15 84(3):407-22. AND Dennis PP, Bremer H. Macromolecular composition during steady-state growth of Escherichia coli B-r. J Bacteriol. 1974 Jul119(1):270-81.PubMed ID4618855, 4600702
Method "The differential rate of r-protein synthesis was calculated from the data in tables 1 [ link ] and 2 [ link ] and the relationship for ar (equation 6, Table 5: ar = (R/P)×[(aa/ribosome) ×fs ×(1–ft)/(nucl./rib)].)." R=RNA,P=Protein, fs=fraction of total RNA that is stable RNA, ft=fraction of stable RNA that is tRNA. Determined also from measurements of the protein content of ribosomes after labeling with radioactive leucine and uridine, see primary refs
Comments "A measure for the synthesis of r-protein is its proportion of total protein, ar. Values of ar have been determined (i) from the protein content of ribosomes and (ii) from the RNA-to protein ratio. Both methods give essentially identical values. The proportion of r-protein increases with growth rate from 9% at 0.6 to 21% at 2.5 doublings per h. It has been reported that the r-protein mRNA synthesis per total RNA synthesis rate is nearly invariant with growth rate, but, when expressed as a fraction of the rate of (total) mRNA synthesis, it increases with growth rate like ar or rRNA synthesis (Fig. 1 refs 42, 63, 89). These observations support the idea that, to a first approximation, r-protein production is matched to rRNA production at the level of transcription." For values at different growth rates see table 3 Table - link . See BNID 106422
Entered by Uri M
ID 102345