Biomaterial Database

Complete amino acid sequence of the alpha 2 heavy chain of a human IgA2 immunoglobulin of the A2m (2) allotype. 1978

A Toraño, and F W Putnam

The complete amino acid sequence of the alpha 2 heavy chain of a human IgA2 immunoglobulin of the A2m(2) allotype has been determined and is compared to the sequence of the alpha 1 chain of the human IgA1 subclass. The characteristic differences between the alpha 1 and alpha 2 chains are greatest in the hinge region and in the location and number of the oligosaccharides. Apart from the duplication in the hinge region of alpha 1 and the deletion in alpha 2, there are 23 amino acid exchanges in the constant (C) regions of the two chains. Accepted mutations are related to the surface accessibility of the residues and the proximity of carbohydrate. The results indicate that human IgA and IgG subclasses arose late in evolution and reflect similar mutationa pressures.

UI	MeSH Term	Description	Entries
D007070	Immunoglobulin A	Represents 15-20% of the human serum immunoglobulins, mostly as the 4-chain polymer in humans or dimer in other mammals. Secretory IgA (IMMUNOGLOBULIN A, SECRETORY) is the main immunoglobulin in secretions.	IgA,IgA Antibody,IgA1,IgA2,Antibody, IgA
D007126	Immunoglobulin Allotypes	Allelic variants of the immunoglobulin light chains (IMMUNOGLOBULIN LIGHT CHAINS) or heavy chains (IMMUNOGLOBULIN HEAVY CHAINS) encoded by ALLELES of IMMUNOGLOBULIN GENES.	Allotypes, Immunoglobulin,Allotypic Antibodies,Antibodies, Allotypic,Ig Allotypes,Allotype, Ig,Allotype, Immunoglobulin,Allotypes, Ig,Allotypic Antibody,Antibody, Allotypic,Ig Allotype,Immunoglobulin Allotype
D007135	Immunoglobulin Variable Region	That region of the immunoglobulin molecule that varies in its amino acid sequence and composition, and comprises the binding site for a specific antigen. It is located at the N-terminus of the Fab fragment of the immunoglobulin. It includes hypervariable regions (COMPLEMENTARITY DETERMINING REGIONS) and framework regions.	Variable Region, Ig,Variable Region, Immunoglobulin,Framework Region, Immunoglobulin,Fv Antibody Fragments,Fv Fragments,Ig Framework Region,Ig Variable Region,Immunoglobulin Framework Region,Immunoglobulin Fv Fragments,Immunoglobulin V,Antibody Fragment, Fv,Antibody Fragments, Fv,Fragment, Fv,Fragment, Fv Antibody,Fragment, Immunoglobulin Fv,Fragments, Fv,Fragments, Fv Antibody,Fragments, Immunoglobulin Fv,Framework Region, Ig,Framework Regions, Ig,Framework Regions, Immunoglobulin,Fv Antibody Fragment,Fv Fragment,Fv Fragment, Immunoglobulin,Fv Fragments, Immunoglobulin,Ig Framework Regions,Ig Variable Regions,Immunoglobulin Framework Regions,Immunoglobulin Fv Fragment,Immunoglobulin Variable Regions,Regions, Immunoglobulin Variable,Variable Regions, Ig,Variable Regions, Immunoglobulin
D007143	Immunoglobulin Heavy Chains	The largest of polypeptide chains comprising immunoglobulins. They contain 450 to 600 amino acid residues per chain, and have molecular weights of 51-72 kDa.	Immunoglobulins, Heavy-Chain,Heavy-Chain Immunoglobulins,Ig Heavy Chains,Immunoglobulin Heavy Chain,Immunoglobulin Heavy Chain Subgroup VH-I,Immunoglobulin Heavy Chain Subgroup VH-III,Heavy Chain Immunoglobulins,Heavy Chain, Immunoglobulin,Heavy Chains, Ig,Heavy Chains, Immunoglobulin,Immunoglobulin Heavy Chain Subgroup VH I,Immunoglobulin Heavy Chain Subgroup VH III,Immunoglobulins, Heavy Chain
D009844	Oligosaccharides	Carbohydrates consisting of between two (DISACCHARIDES) and ten MONOSACCHARIDES connected by either an alpha- or beta-glycosidic link. They are found throughout nature in both the free and bound form.	Oligosaccharide
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein