title: Strategy for affinity maturation of an antibody with high evolvability to (4-hydroxy-3-nitrophenyl) acetyl hapten.
abstract: In order to quantitate the contribution of amino acid replacements to an increase in affinity during affinity maturation, we measured thermodynamic parameters of the antigen-antibody interaction for a group of anti-(4-hydroxy-3-nitrophenyl) acetyl monoclonal antibodies whose differences in amino acid sequences had arisen only from somatic hypermutation. We prepared a common ancestor and hypothetical intermediate clones that might occur on the affinity maturation pathway, by employing site-directed mutagenesis. Isothermal calorimetric titration of the antigen-antibody reaction revealed that antibody evolution proceeds in two steps. The first step is driven by a decrease in enthalpy, in which two amino acid replacements in the VL region play an essential role. Further accumulation of amino acid replacements in VH and VL regions during the second step induce a progressive increase in affinity, which is driven by an increase in entropy, which has a cooperative mutational effect.
authors.affiliation: Age Dimension Research Center, National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Furukawa
authors.forename: Takeyuki
authors.initials: T
authors.lastname: Shimizu
authors.forename: Akikazu
authors.initials: A
authors.lastname: Murakami
authors.forename: Ryo
authors.initials: R
authors.lastname: Kono
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Nakagawa
authors.forename: Takuma
authors.initials: T
authors.lastname: Sagawa
authors.forename: Ichiro
authors.initials: I
authors.lastname: Yamato
authors.forename: Takachika
authors.initials: T
authors.lastname: Azuma
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D015119:Aminocaproic Acid / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D000915:Antibody Affinity / Q000276:immunology*; D000917:Antibody Formation / Q000276:immunology*; D002151:Calorimetry; D002942:Circular Dichroism; D002999:Clone Cells; D006241:Haptens / Q000276:immunology*; D007143:Immunoglobulin Heavy Chains / Q000737:chemistry; D007147:Immunoglobulin Light Chains / Q000737:chemistry; D007135:Immunoglobulin Variable Region / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009596:Nitrophenols / Q000276:immunology*; D010648:Phenylacetates; D011487:Protein Conformation; D013816:Thermodynamics
chemical_list: D000911:Antibodies, Monoclonal; D006241:Haptens; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D007135:Immunoglobulin Variable Region; D009596:Nitrophenols; D010648:Phenylacetates; C026242:4-hydroxy-5-nitrophenyl acetic acid; D015119:Aminocaproic Acid