Figure 2.

Schematic presentation of the single-chain technology used for generating the α345 NC1 trimer. A single polypeptide combines NC1 monomers of α3, α4, and α5 chains via artificial linkers analogous to native linkers between C4 subdomains within each monomer. Short linkers restrict orientation of monomers in a way that the C4₂ subdomain of the α3 chain will interface with the C4₁ subdomain of the α4 chain and the C4₂ subdomain of the α4 chain will interface with the C4₁ subdomain of the α5 chain. Finally, the C4₂ subdomain of the α5 chain will interface with the C4₁ subdomain of the α3 chain in the folded single-chain α345 NC1 trimer. The same strategy was applied to generate α543, α343, and α545 forms of the single-chain NC1 trimer.