3A67

Crystal Structure of HyHEL-10 Fv mutant LN31D complexed with hen egg white lysozyme

Summary for 3A67

• Entry DOI: 10.2210/pdb3a67/pdb
• Related: 1C08 1J1O 1J1P 1J1X 2DQI 2DQJ 3A6B 3A6C
• Descriptor: Lysozyme binding ig kappa chain V23-J2 region, IG VH, anti-lysozyme, Lysozyme C, ... (4 entities in total)
• Functional Keywords: antigen-antibody complex, mutant, immune system-hydrolase complex, allergen, antimicrobial, bacteriolytic enzyme, disulfide bond, glycosidase, immune system/hydrolase
• Biological source: Mus musculus (house mouse); More
• Cellular location: Secreted: P00698
• Total number of polymer chains: 3
• Total formula weight: 38751.89

Authors

Yokota, A.,Tsumoto, K.,Shiroishi, M.,Nakanishi, T.,Kondo, H.,Kumagai, I. (deposition date: 2009-08-24, release date: 2009-12-22, Last modification date: 2023-11-01)

Primary citation

Yokota, A.,Tsumoto, K.,Shiroishi, M.,Nakanishi, T.,Kondo, H.,Kumagai, I.
Contribution of asparagine residues to the stabilization of a proteinaceous antigen-antibody complex, HyHEL-10-hen egg white lysozyme
J.Biol.Chem., 285:7686-7696, 2010

PubMed Abstract: Many germ line antibodies have asparagine residues at specific sites to achieve specific antigen recognition. To study the role of asparagine residues in the stabilization of antigen-antibody complexes, we examined the interaction between hen egg white lysozyme (HEL) and the corresponding HyHEL-10 variable domain fragment (Fv). We introduced Ala and Asp substitutions into the Fv side chains of L-Asn-31, L-Asn-32, and L-Asn-92, which interact directly with residues in HEL via hydrogen bonding in the wild-type Fv-HEL complex, and we investigated the interactions between these mutant antibodies and HEL. Isothermal titration calorimetric analysis showed that all the mutations decreased the negative enthalpy change and decreased the association constants of the interaction. Structural analyses showed that the effects of the mutations on the structure of the complex could be compensated for by conformational changes and/or by gains in other interactions. Consequently, the contribution of two hydrogen bonds was minor, and their abolition by mutation resulted in only a slight decrease in the affinity of the antibody for its antigen. By comparison, the other two hydrogen bonds buried at the interfacial area had large enthalpic advantage, despite entropic loss that was perhaps due to stiffening of the interface by the bonds, and were crucial to the strength of the interaction. Deletion of these strong hydrogen bonds could not be compensated for by other structural changes. Our results suggest that asparagine can provide the two functional groups for strong hydrogen bond formation, and their contribution to the antigen-antibody interaction can be attributed to their limited flexibility and accessibility at the complex interface.

PubMed: 20038580
DOI: 10.1074/jbc.M109.089623

Experimental method

X-RAY DIFFRACTION (1.8 Å)