Salt Links Dominate Affinity of Antibody HyHEL-5 for Lysozyme through Enthalpic Contributions*
| dc.contributor.author | Wibbenmeyer, Jamie A. | |
| dc.contributor.author | Schuck, Peter | |
| dc.contributor.author | Smith-Gill, Sandra J. | |
| dc.contributor.author | Willson, Richard C. | |
| dc.date.accessioned | 2020-03-11T17:16:55Z | |
| dc.date.available | 2020-03-11T17:16:55Z | |
| dc.date.issued | 1999-09 | |
| dc.description.abstract | The binding of murine monoclonal antibody HyHEL-5 to lysozyme has been the subject of extensive crystallographic, computational, and experimental investigations. The complex of HyHEL-5 with hen egg lysozyme (HEL) features salt bridges between Fab heavy chain residue Glu50, and Arg45 and Arg68 of HEL. This interaction has been predicted to play a dominant role in the association on the basis of molecular electrostatics calculations. The association of aspartic acid and glutamine mutants at position 50H of the cloned HyHEL-5 Fab with HEL and bobwhite quail lysozyme (BQL), an avian variant bearing an Arg68 ? Lys substitution in the epitope, was characterized by isothermal titration calorimetry and sedimentation equilibrium. Affinities for HEL were reduced by 400-fold (E50HD) and 40,000-fold (E50HQ) (??G� estimated at 4.0 and 6.4 kcal mol?1, respectively). The same mutations reduce affinity for BQL by only 7- and 55-fold, respectively, indicating a reduced specificity for HEL. The loss of affinity upon mutation is in each case primarily due to an unfavorable change in the enthalpy of the interaction; the entropic contribution is virtually unchanged. An enthalpy-entropy compensation exists for each interaction; ?H� decreases, while ?S� increases with temperature. The ?Cp for each mutant interaction is less negative than the wild-type. Mutant-cycle analysis suggests the mutations present in the HyHEL-5 Fab mutants are linked to those present in the BQL with coupling energies between 3 and 4 kcal mol?1. | |
| dc.identifier.citation | Copyright 1999 Journal of Biological Chemistry. Recommended citation: Wibbenmeyer, Jamie A., Peter Schuck, Sandra J. Smith-Gill, and Richard C. Willson. "Salt links dominate affinity of antibody HyHEL-5 for lysozyme through enthalpic contributions." Journal of Biological Chemistry 274, no. 38 (1999): 26838-26842. doi: 10.1074/jbc.274.38.26838. URL: http://www.jbc.org/content/274/38/26838.short. Reproduced in accordance with the original publisher's licensing terms and with permission from the authors. | |
| dc.identifier.uri | https://hdl.handle.net/10657/6235 | |
| dc.language.iso | en_US | |
| dc.publisher | Journal of Biological Chemistry | |
| dc.title | Salt Links Dominate Affinity of Antibody HyHEL-5 for Lysozyme through Enthalpic Contributions* | |
| dc.type | Article |