1yuh
From Proteopedia
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FAB FRAGMENT
Overview
Affinity maturation of the immune response to nitrophenol-containing, antigens has been extensively investigated. Significant strides made, during the past several years with the advent of PCR technology have, provided a wealth of biochemical knowledge. Structural investigations of, the phenomena have however been limited. We have determined the, three-dimensional structure of the Fab fragment of 88C6/12, an, anti-4-hydroxy-3-nitrophenyl acetic acid antibody complexed with the, immunizing hapten and with a heteroclitic iodinated hapten. The, crystallographic structure of the complexes reveals that the binding is, stabilized by a number of hydrogen bonds and extensive van der Waals, interactions between the hapten and the antibody. In addition, the Fab, binding pocket contains a region of positive electrostatic potential well, suited for interaction with the predominant resonance form of the, nitrophenyl ring system. The observed heteroclicity towards the iodinated, hapten is not a direct result of iodine-protein interactions, but results, from the enhanced stability in the iodinated ring of the resonance form, that binds the antibody. In addition this investigation provides a, rationale for the strong preference for the substitution in the heavy, chain from the germ-line gene encoded Trp 33 to Leu 33 in the mature, anti-nitrophenol response.
About this Structure
1YUH is a Protein complex structure of sequences from [1] with NP as ligand. Full crystallographic information is available from OCA.
Reference
Structural analysis of affinity maturation: the three-dimensional structures of complexes of an anti-nitrophenol antibody., Yuhasz SC, Parry C, Strand M, Amzel LM, Mol Immunol. 1995 Oct;32(14-15):1143-55. PMID:8544863
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