This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1jfq
From Proteopedia
|
ANTIGEN-BINDING FRAGMENT OF THE MURINE ANTI-PHENYLARSONATE ANTIBODY 36-71, "FAB 36-71"
Overview
Alanine 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.
About this Structure
1JFQ is a Protein complex structure of sequences from Mus musculus. Full crystallographic information is available from OCA.
Reference
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
Page seeded by OCA on Fri Feb 15 16:07:12 2008
