Trinucleotide cassettes increase diversity of T7 phage-displayed peptide library

BMC Biotechnology

Table 1 Amino acid sequence diversity of proteomes and libraries

	Average diversity per position	Diversity per 12-mer	Functional diversity (# of equally probable sequences)
Proteomes:
Human	0.85	0.14	5.73 × 10¹⁴
E. coli	0.82	0.09	3.69 × 10¹⁴
Phage-displayed libraries:
T7 Trinuc	0.91	0.32	1.31 × 10¹⁵
T7 NNK	0.85	0.14	5.73 × 10¹⁴
M13 NNK	0.68	0.01	4.10 × 10¹³
In silico libraries:
20 codon (trinucleotide)	1.00	1.00	4.10 × 10¹⁵
32 codon (reduced)	0.83	0.11	4.51 × 10¹⁴
61 codon (standard)	0.79	0.06	2.46 × 10¹⁴

Populations of random 12-mer peptides from the human and E. coli proteomes and from computationally-random in silico libraries were collected as previously described and were subjected to diversity analysis by the DIVAA program of the RELIC web server [4]. DIVAA-generated positional diversity estimates were utilized to calculate the average positional diversity estimates for the peptide populations. Diversity per 12-mer was determined by raising the average positional diversity to the twelth-power. Functional diversity [6] was estimated by multiplying the diversity per 12-mer by the total number of possible sequences (20¹² for a 12-mer peptide population). Portions of this table were reproduced with kind permission from Wiley-VCH Verlag GmbH & Co. KGaA, see acknowledgements section for details.

ISSN: 1472-6750