Cytochrome b562 Library Construction

Creative Biolabs provides the unique cytochrome b562 phage display library construction service for global customers. Our innovative Hi-Affi™ phage display platform is applied for this scaffold protein library generation, which can provide higher affinity and diversity than that of other technology.

Cytochrome b562 is one 106 residues heme group of about 12,000 molecular weight. It non-covalently binds to cytochrome b which is a protein found in the mitochondria of eukaryotic cells. Cytochrome b562, interestingly, is a kind of whole α-helical protein that folds into a natural four-helix bundle. This four-helix bundle protein is relatively small, but thermally stable, which owe to its well-packed hydrophobic core providing a rigid framework structure. In addition, the relevant three-dimensional structure analysis has shown two loops linking the α-helical framework, each one connecting a pair of the α-helices and coming together at one end of the helix bundle which opposites to the heme-binding site.

Ideal cytochrome b562 scaffold is stable mutant selected from cytochrome b562 phage display library with randomly alter ligand binding properties. The library is constructed base on randomized the residues of two loops respectively and display on phage surface. The library is then selected against the bovine serum albumin conjugate of N-methyl-p-nitrobenzylamine derivative 1 (BSA-1) to isolate mutants that can bind an epitope consisting of the ligand N-methyl-p-nitrobenzylamine derivative 1 and the carrier protein. It is reported that the cytochrome b562 scaffold was chosen as an alternate framework for the selection of an artificial hapten-binding protein in a study by Ku and Schultz (1995).

The Hi-Affi™ phage display platform has been developed by Creative Biolabs for improving our library generation. This proprietary platform is based on traditional phage display technology, which is an exogenous gene expression method through fusing the target genes to bacteriophage coat proteins then displaying on the phage surfaces to select specific binders. Moreover, it also integrates trimer codon technology and NNK method together to introduce more diversity for constructed libraries. This platform is more suitable for sorting and isolating the high affinity protein or peptide targets, which can improve our cytochrome b562 phage display library to achieve 100% precise mutant and over 1010 diversity.

Creative Biolabs has years of research and development experience for the generation of custom scaffold protein libraries. Our devoted scientists, who have generated about 55 kinds of scaffold libraries for global customers, are confident in offering the best scaffold protein library with highest quality and efficiency.

Cytochrome b562 Library Construction
Fig. 1 Crystal structure of b562RIL, a redesigned four helix bundle. (PDB ID: 1M6T)


  1. Ku, J. and Schultz, P. G. (1995) 'Alternate protein frameworks for molecular recognition', Proceedings of the National Academy of Sciences, 92(14), 6552-6556.

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