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[An amino acid substitution determining G1m(x) allotypic marker]
Nihon Hoigaku Zasshi = the Japanese Journal of Legal Medicine
|April 1, 1989
Summary
The G1m(x) allotypic marker in human IgG1 is caused by a glycine substitution at position 431, replacing alanine. This finding clarifies the primary structure basis for this important immunoglobulin marker.
Area of Science:
- Immunogenetics
- Protein Chemistry
- Structural Biology
Context:
- The G1m(x) allotypic marker is a significant human immunoglobulin G1 (IgG1) polymorphism.
- Previous estimations of the G1m(x) marker's basis relied on indirect methods.
Purpose:
- To identify the specific amino acid substitution responsible for the G1m(x) allotypic marker.
- To analyze the primary structure of IgG1-Fc fragments to pinpoint the genetic variation.
Summary:
- Primary structure analysis of C-terminal BrCN peptides from human IgG1 revealed that the G1m(x+) allotype has glycine at position 431 (Eu numbering), whereas the G1m(x-) allotype has alanine.
- This amino acid substitution at position 431 is confirmed as the molecular basis for the G1m(x) allotypic marker.
Impact:
- Provides a definitive molecular explanation for the G1m(x) allotypic marker.
- Facilitates understanding of IgG1 structure-function relationships and antibody diversity.
- Contributes to the study of antibody epitopes and tertiary structure interactions within the IgG1-Fc fragment.