Evolutionary approaches in protein engineering towards biomaterial construction

Abstract

The tailoring of proteins for specific applications by evolutionary methods is a highly active area of research. Rational design and directed evolution are the two main strategies to reengineer proteins or create chimeric structures. Rational engineering is often limited by insufficient knowledge about proteins' structure-function relationships; directed evolution overcomes this restriction but poses challenges in the screening of candidates. A combination of these protein engineering approaches will allow us to create protein variants with a wide range of desired properties. Herein, we focus on the application of these approaches towards the generation of protein biomaterials that are known for biodegradability, biocompatibility and biofunctionality, from combinations of natural, synthetic, or engineered proteins and protein domains. Potential applications depend on the enhancement of biofunctional, mechanical, or other desired properties. Examples include scaffolds for tissue engineering, thermostable enzymes for industrial biocatalysis, and other therapeutic applications.

Fig. 1. Structural outline of protein engineering strategies.

Fig. 2. Strategy to enhance the structural and functional properties of biomolecules.

Fig. 3. Steps involved in the rational design of multifunctional modular protein engineered biomaterial construction.

Fig. 4. Schematics depicting the bottom up approach to generate macroscopic protein biomaterials following rational design strategy.

Fig. 5. Schematics showing the method of fragment recombination used to construct hybrid proteins from the two distantly related or non-related parent proteins 1 and 2.

Fig. 6. Illustration on the variation in mechanical properties upon protein recombination. Three different kinds of unfolding events: (a) stable, (b) dual, (c) labile from the hybrids with tandem repeats of immunoglobulin like domains (hybrids) and B1 domain of Protein G (GB1-hybrid)₄ displaying multiple contour lengths. The thick lines in the force extension curve depict the unfolding event of the hybrids while the normal lines represent for GB1.

Fig. 7. Schematic representing the construction of biomaterials from the proteins evolved through directed evolution (Left). The various steps involved and the variation in properties as we move from microscopic (single molecule/ensemble level to macroscopic biomaterials is also shown (Right).

Brindha J.

Balamurali M. M.

Kaushik Chanda