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ANTIGEN-BINDING FRAGMENT OF THE MURINE ANTI-PHENYLARSONATE ANTIBODY 36-71, "FAB 36-71"
Structural highlights
FunctionEvolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedAlanine scanning was used to determine the affinity contributions of 10 side chain amino acids (residues at position 50-60 inclusive) of H chain complementarity-determining region 2 (HCDR2) of the somatically mutated high-affinity anti-p-azophenylarsonate Ab, 36-71. Each mutated H chain gene was expressed in the context of mutated (36-71L) and the unmutated (36-65L) L chains to also assess the contribution of L chain mutations to affinity. Combined data from fluorescence quenching, direct binding, inhibition, and capture assays indicated that mutating H:Tyr(50) and H:Tyr(57) to Ala in the 36-71 H chain results in significant loss of binding with both mutated (36-71L) or unmutated (36-65L) L chain, although the decrease was more pronounced when unmutated L chain was used. All other HCDR2 mutations in 36-71 had minimal effect on Ab affinity when expressed with 36-71 L chain. However, in the context of unmutated L chain, of H:Gly(54) to Ala resulted in significant loss of binding, while Abs containing Asn(52) to Ala, Pro(53) to Ala, or Ile(58) to Ala mutation exhibited 4.3- to 7.1-fold reduced affinities. When alanine scanning was performed instead on certain HCDR2 residues of the germline-encoded (unmutated) 36-65 Ab and expressed with unmutated L chain as Fab in bacteria, these mutants exhibited affinities similar to or slightly higher than the wild-type 36-65. These findings indicate an important role of certain HCDR2 side chain residues on Ab affinity and the constraints imposed by L chain mutations in maintaining Ag binding. Structural analysis of mutants of high-affinity and low-affinity p-azophenylarsonate-specific antibodies generated by alanine scanning of heavy chain complementarity-determining region 2.,Parhami-Seren B, Viswanathan M, Strong RK, Margolies MN J Immunol. 2001 Nov 1;167(9):5129-35. PMID:11673524[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences | ||||||||||||||||||
