GroEL-A Versatile Chaperone for Engineering and a Plethora of Applications

Abstract

Chaperones play a vital role in the life of cells by facilitating the correct folding of other proteins and maintaining them in a functional state, being themselves, as a rule, more stable than the rest of cell proteins. Their functional properties naturally tempt investigators to actively adapt them for biotechnology needs. This review will mostly focus on the applications found for the bacterial chaperonin GroE and its counterparts from other organisms, in biotechnology or for research purposes, both in their engineered or intact versions.

Keywords: GroEL; chaperones in biotechnology; chaperonin; engineering of chaperones.

Figure 1

The forms of chaperonin GroEL that find applications in biotechnology: (a) Full-sized GroE complex consisting of two rings formed by seven GroEL monomers each (grey and red) and one ring of seven GroES monomers (green). (b) GroEL 14-mer. (c) GroEL heptamer ring. Shown is its end-on view. One of the monomers is shown in blue. (d) GroEL monomer separately, its apical domain is shown in beige. (e) GroEL apical domain separately. The published structure of T. thermophilus GroEL available in pdb-bank (PDB 2C7D) was used. The program I-TASSER™ Software (“PROGRAM”) (https://zhanggroup.org/I-TASSER/, accessed on 18 February 2022) [13,14,15] was used for manipulations with the structure.

Figure 2

Consecutive changes in T. thermophilus GroEL as a carrier for peptide biosynthesis: (a) Initial T. thermophilus GroEL monomer. Methionine residues are shown in blue, amino acid residues 199–201 for introducing the polylinker are shown in green. (b) The introduced polylinker (corresponding amino acid residues Gly-Ser-Lys-Leu-Glu-Phe) is shown in red. (c) Modified T. thermophilus GroEL with polyphemusin I incorporated into its polypeptide chain. (d) Modified T. thermophilus GroEL with enfuvirtide incorporated into its polypeptide chain. To illustrate the position of inserts, the published structure of T. thermophilus GroEL available in pdb-bank (PDB 1SRV) was used. The program I-TASSER™ Software (“PROGRAM”) (https://zhanggroup.org/I-TASSER/, accessed on 18 February 2022) [13,14,15] was used for manipulations with the structure.

Figure 3

GrAD (a) and its permutated variants. The substrate-binding surface is formed by the helices 8, 9, and N (shown in green, blue, and purple, respectively). In (b,c), the three amino acid long linker connecting initial N- and C-termini is red. For manipulations with the structure (PDB 1SRV) the program I-TASSER™ Software (“PROGRAM”) (https://zhanggroup.org/I-TASSER/, accessed on 18 February 2022) [13,14,15] was used.