Fraction of proteins that are present in less than 10 copies per cell

Range ≥10 % of proteins
Organism Bacteria Escherichia coli
Reference Okumus B et al., Mechanical slowing-down of cytoplasmic diffusion allows in vivo counting of proteins in individual cells. Nat Commun. 2016 May 18 7: 11641. doi: 10.1038/ncomms11641 p.2 left column top paragraphPubMed ID27189321
Primary Source [4] Taniguchi Y et al., Quantifying E. coli proteome and transcriptome with single-molecule sensitivity in single cells. Science. 2010 Jul 30 329(5991):533-8. doi: 10.1126/science.1188308 [5] Schmidt A et al., The quantitative and condition-dependent Escherichia coli proteome. Nat Biotechnol. 2016 Jan34(1):104-10. doi: 10.1038/nbt.3418PubMed ID20671182, 26641532
Comments P.2 left column top paragraph: "A surge of single-cell fluorescence studies has shown that genetically identical cells residing within the same environment can display extensive cell-to-cell variability in the expression levels of various proteins [refs 1,2,3]. A substantial challenge when analysing these phenomena is that the heterogeneity typically originates in reactions involving low-abundance components, while only the high-abundance components that indirectly respond to the heterogeneity are relatively straightforward to measure. For example, many of the key regulatory proteins in Escherichia coli (E. coli) are present in such few copies—recent studies suggest that at least 10% of the proteins in E. coli are present in <10 copies per cell [primary sources]—that fluorescent protein (FP) fusions are difficult to detect over the cellular auto-fluorescence [ref 6]."
Entered by Uri M
ID 114115