Figure 6
From: Ancestral protein resurrection and engineering opportunities of the mamba aminergic toxins
Affinity and structure analysis of CM-3, AncTx4 and ρ-Da1a toxins on adrenoceptors. (A) pKi values are reported for CM-3, AncTx4 and ρ-Da1a on the 4 adrenoceptors α1A, α1B, α1D and α2C. (B) The X-ray structure of ρ-Da1a K34A (code PDB: 4IYE), the position 43 is in the top of the third loop quite far and on the opposite side compare to the substitution S38I. The lateral chain of Ala43 is surrounded by the phenyl ring of Phe25, the side chain of Leu23, and by oxygen atoms from Cys42 and Thr45 main chains. This region of the globular core is indeed compact. Hence the substitution A43V has to reorganize the packing to accommodate the bigger lateral chain of the valine.
