Journal of Biochemistry Advance Access originally published online on August 19, 2008
Journal of Biochemistry 2008 144(5):591-598; doi:10.1093/jb/mvn103
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© 2008 The Japanese Biochemical Society
Construction of a Fully Synthetic Human scFv Antibody Library with CDR3 Regions Randomized by a Split–Mix–Split Method and Its Application

1National Laboratory of Biomacromolecules, and CAS-UT joint laboratory of Structural Virology and Immunology, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101; and 2Beijing ABT Genetic Engineering Technology Co., Ltd, Beijing, 102206, China
*To whom correspondence should be addressed. Tel/Fax: +86-10-80726906, E-mail: hlhuang{at}genetics.ac.cn
Correspondence may also be addressed: Tel: +86-10-64888583, Fax: +86-10-64888584, E-mail: yanxy{at}sun5.ibp.ac.cn
Received May 1, 2008; Accepted August 13, 2008
| Abstract |
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The randomization scheme of hypervariable region takes crucial role in construction of a synthetic antibody library. The codon bias and inevitable stop codon of conventional NNK and NNS codons limit their applications. Here we report a split–mix–split DNA synthesis method that can control over the amino acid composition and distribution of randomized sequences effectually. A fully synthetic human antibody library with a diversity of 1.56 x 109 was successfully generated with complementarity determining region 3 (CDR3) randomized by this strategy. Sequencing analysis indicated that >60% of colonies had completely correct scFv genes and the amino acid composition and distribution were designed well in accordance. The utility was demonstrated by screening of scFv clones against BHL (anti-CD3 x anti-ovarian carcinoma bispecific antibody). These results proved the feasibility of the split–mix–split DNA randomization strategy in library construction and site-directed mutagenesis.
Key Words: antibody library, biopanning, phage display, randomization, single-chain antibody
Abbreviations:
BHL, anti-CD3 x anti-ovarian carcinoma bispecific single-chain antibody; CDR, complementarity determining region; HuCAL, fully gene-synthetic human combinatoryial antibody library; scFv, single-chain variable fragment; SMS, split–mix–split DNA synthesis; SOE PCR, splice overlap extension PCR; TRIM, trinucleotide-mutagenesis; VH, variable region of heavy chain; VL, variable region of light chain; V
, variable regionof
light chain; V
, variable region of
light chain