Creative Biolabs provides custom scaffold library construction services for DARPin, a non-immunological alternative for traditional Ig-based scaffolds. Our innovative scientists have developed the powerful HiAffi™ display platform for the generation of scaffold libraries with satisfactory controllability and operability.
Introduction of DARPin
Designed ankyrin repeat proteins (DARPins) belong to a novel class of small nonimmunoglobulin protein scaffold derived from natural ankyrin repeat proteins. Ankyrin repeat proteins are one of the most common binding proteins in nature and responsible for diverse functions, such as cell signaling and receptor binding. The basic structure of ankyrin repeat proteins is formed by a β-turn followed by two antiparallel α-helices and a loop connected to the β-turn of the next repeat. DARPin is composed of a number of repeat motifs proteins, usually consists of four or five repeats, which is about 14 kDa or 18 kDa.
Fig.1 Crystal structure of DARPin (PDB 2JAB)
Features and Applications of DARPin
DARPins are featured by their large and modular target interaction surfaces. A unique feature of such surfaces is that they can be adapted to the target size by adjusting the number of repeats in the protein. Successful examples with high affinity against a variety of targets have been reported. It is suggested that DARPins are suited not only for novel fusions and conjugates and extracellular targeting use but also for intracellular applications, because of their high thermodynamic stability, reversible folding behavior, high solubility, high yield in E. coli, the absence of cysteines and low aggregation tendencies. Therefore, DARPins is considered to offer advantages over antibodies in the discovery and development of drug therapy.
DARPin Library Construction
Currently, various DARPins have been selected through display technology and the use of the SRP (signal recognition particle) pathway also ensures the efficient display of stable and fast-folding DARPins. Creative Biolabs adopts the advanced Hi-Affi™ platform to provide a high-quality controllable DARPin library. This platform allows making random regions with each AA position randomized with a defined AA composition as well as region length variation with the least bias. During the construction of DARPin library, naturally conserved residues would be defined as invariant framework residues and variable amino acid positions can be subjected to randomization. The randomized positions were fixed according to sequence statistics and structural considerations.
Own Your Unique DARPin Library
In this case, there could be maximum 7 randomized residues (6 interaction residues and 1 framework residue, while randomized position 33 of the AR module was rarely involved in protein interactions and thus usually defined as invariant serine) on each designed AR module and also varying number of designed AR module for one DARPin library design. Based on our proprietary Hi-Affi™ display platform, Creative Biolabs is able to generate DARPin libraries with desired bias and high diversity. Our clients can feel free to design each specific randomized positions to achieve unique DARPin library for their specific projects.
Meanwhile, Creative Biolabs can offer custom DARPins library with a diversity of 1010 variants to satisfy either pharmaceuticals or research applications. The diversity of formats and robustness of DARPins have great potential to overcome a limitation of current therapeutic approaches for a chosen disease. This will significantly speed up the R&D process in drug invention.
Features of Our Hi-Affi™ Platform
Creative Biolabs commits to the research and development of scaffold protein area. Combining with our well-recognized Hi-Affi™ display platform, our scientists are confident in offering 100% precise mutant library construction with the expected size of over 1010 to meet our global clients’ most specific research objective. If you are interested in our DARPin scaffold library construction service, please do not hesitate to inquire us for more details.