%0 Journal Article
%T A Trade-off Between Thermostability and Binding Affinity of Anti-(4-hydroxy-3-nitrophenyl)Acetyl Antibodies During the Course of Affinity Maturation.
%A Nishiguchi A
%A Murakami A
%A Azuma T
%A Oda M
%A Nishiguchi A
%A Murakami A
%A Azuma T
%A Oda M
%A Nishiguchi A
%A Murakami A
%A Azuma T
%A Oda M
%J Protein J
%V 41
%N 2
%D Apr 2022
%M 35501455
%F 4
%R 10.1007/s10930-022-10053-w
%X Somatic hypermutation (SHM) is one of the driving forces that increases antibody (Ab) affinity. We studied the effects of SHM on thermostability and affinity using three single-chain Fv fragments (scFvs) of anti-(4-hydroxy-3-nitrophenyl)acetyl Abs, namely 9TG, 9T7, and E11. 9TG has a germline structure that lacks SHM and is an ancestor of 9T7 with 11 mutations. E11, which has 21 mutations, is a mature Ab and has its own ancestor. The thermostabilities and antigen-Ab interactions were analyzed by circular dichroism (CD), differential scanning calorimetry (DSC), and isothermal titration calorimetry (ITC). Far-UV CD spectra showed that all scFvs were folded into a structure referred to as immunoglobulin-fold and were unfolded by heating at different melting temperatures. Comparison of thermodynamic parameters obtained from DSC and ITC revealed that the magnitude of stabilization free energy at 37 °C was in the order, 9TG > 9T7 > E11, while that of the free energy of interaction with antigen was 9TG < 9T7 < E11, suggesting that Abs make a trade-off between stability and affinity during affinity maturation.