1ic7
From Proteopedia
CRYSTAL STRUCTURE OF HYHEL-10 FV MUTANT(HD32A99A)-HEN LYSOZYME COMPLEX
Structural highlights
Function[LYSC_CHICK] Lysozymes have primarily a bacteriolytic function; those in tissues and body fluids are associated with the monocyte-macrophage system and enhance the activity of immunoagents. Has bacteriolytic activity against M.luteus.[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedA structural and thermodynamic study of the entropic contribution of salt bridge formation to the interaction between hen egg white lysozyme (HEL) and the variable domain fragment (Fv) of anti-HEL antibody, HyHEL-10, was carried out. Three Fv mutants (HD32A, HD96A, and HD32AD96A) were prepared, and the interactions between the mutant Fvs and HEL were investigated. Crystallography revealed that the overall structures of these mutant complexes were almost identical to that of wild-type Fv. Little structural changes were observed in the HD32AD96A mutant-HEL complex, and two water molecules were introduced into the mutation site, indicating that the two water molecules structurally compensated for the complete removal of the salt bridges. This result suggests that the entropic contribution of the salt bridge originates from dehydration. In the singly mutated complexes, one water molecule was also introduced into the mutated site, bridging the antigen-antibody interface. However, a local structural difference was observed in the HD32A Fv-HEL complex, and conformational changes occurred due to changes in the relative orientation of the heavy chain to the light chain upon complexation in HD96A Fv-HEL complexes. The reduced affinity of these single mutants for the antigen originates from the increase in entropy loss, indicating that these structural changes also introduced an increase in entropy loss. These results suggest that salt bridge formation makes an entropic contribution to the protein antigen-antibody interaction through reduction of entropy loss due to dehydration and structural changes. Structural evidence for entropic contribution of salt bridge formation to a protein antigen-antibody interaction: the case of hen lysozyme-HyHEL-10 Fv complex.,Shiroishi M, Yokota A, Tsumoto K, Kondo H, Nishimiya Y, Horii K, Matsushima M, Ogasahara K, Yutani K, Kumagai I J Biol Chem. 2001 Jun 22;276(25):23042-50. Epub 2001 Apr 10. PMID:11297547[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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