Calculating complexity of large randomized libraries.
Randomized libraries are increasingly popular in protein engineering and other biomedical research fields. Statistics of the libraries are useful to guide and evaluate randomized library construction. Previous works only give the mean of the number of unique sequences in the library, and they can only handle equal molar ratio of the four nucleotides at a small number of mutation sites. We derive formulas to calculate the mean and variance of the number of unique sequences in libraries generated by cassette mutagenesis with mixtures of arbitrary nucleotide ratios. Computer program was developed which utilizes arbitrary numerical precision software package to calculate the statistics of large libraries. The statistics of library with mutations in more than 20 amino acids can be calculated easily. Results show that the nucleotide ratios have significant effects on these statistics. The more skewed the ratio, the larger the library size is needed to obtain the same expected number of unique sequences. The program is freely available at http://graphics.med.yale.edu/cgi-bin/lib_comp.pl.
Department of Molecular Biophysics and Biochemistry, W.M. Keck Foundation Biotechnology Resource Laboratory, Yale University, 333 Cedar Street, New Haven, CT 06510, USA. yong.kong@yale.edu
Yong
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Kong
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019295:Computational Biology; D019020:Directed Molecular Evolution; D006801:Humans; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D019151:Peptide Library; D015202:Protein Engineering
D019151:Peptide Library