TABLE 5.

Qualitative assessment of the fraction of ribosomal proteins exhibiting charge segregation

This analysis was performed upon visual inspection of the electrostatic surface area of 193 ribosomal proteins. N.A., not applicable.

Organism	Protein Data Bank file	Proteins in large ribosomal subunita
		Low pI		High pI
		Total number of proteins	Fraction of proteins exhibiting charge segregation	Total number of proteins	Fraction of proteins exhibiting charge segregation
			%		%
Non-halophiles
Bacteria
E. coli	2AW4	2	100b	27	85
T. thermophilus	3I8I	2	100b	29	90
D. radiodurans	2ZJR	1	100b	24	83
Eukaryota
S. cerevisiae	3U5E	5c	80	37	70
T. thermophila	4A1D 4A1E	0	N.A.	39	62
Halophiles
Halophilic archaea
H. marismortui	2QA4	18	100	9	100

^a Note that not all existing ribosomal proteins are listed in the Protein Data Bank files (20) used as source of three-dimensional coordinates.

^b Note the small sample size.

^c Protein Data Bank files for P0, P1α, and P2β are chains q, r, and s of 4B6A (42), respectively.