IMGT®, the international ImMunoGeneTics information system®

Numbering

The IMGT unique numbering has been defined by Marie-Paule Lefranc [1-5], in order to easily compare sequences of IG and TR from all vertebrates species, and, by extension, sequences with an immunoglobulin-like domain (IMGT Scientific chart).

The 'IMGT unique numbering' concept [3] is part of the 'NUMEROTATION' concept of IMGT-ONTOLOGY[6]

The IMGT unique numbering provides positions of the amino acids (and corresponding codons) in coding sequences, in 2D graphical representations or IMGT Colliers de Perles [7], and in 3D structures (IMGT/3Dstructure-DB) [8].

In the IMGT unique numbering for V-DOMAIN [4] and in the IMGT unique numbering for C-DOMAIN [5], conserved amino acids from frameworks always have the same number whatever the IG or TR chain type, whatever the domain (variable or constant), and whatever the species they come from. As examples: cysteine 23 (1st-CYS, in strand B), tryptophan 41 (CONSERVED-TRP, in strand C), hydrophobic 89 (in strand E) and cysteine 104 (2nd-CYS, in strand F).

Correspondence between numberings [4] is available in IMGT Scientific chart and in ref. [4] and [9].

The IMGT unique numbering also applied to V-LIKE-DOMAIN [4] and C-LIKE-DOMAIN [5] of proteins (other than IG or TR) of the immunoglobulin superfamily (IgSF).

The 'IMGT unique numbering' concept has also been extended to the MH G-DOMAIN and to the G-LIKE-DOMAIN of proteins (other than MH) of the MH superfamily (MhSF).

Citing IMGT:
Lefranc, M.-P.
"IMGT, the international ImMunoGeneTics information system®"
Nucl. Acids Res., 33, D593-D597 (2005) Full text, PMID: 15608269, LIGM:291

Citing the IMGT unique numbering for V-DOMAIN and V-LIKE-DOMAIN:
Lefranc, M.-P., Pommié, C., Ruiz, M., Giudicelli, V., Foulquier, E., Truong, L., Thouvenin-Contet, V. and Lefranc, G.
"IMGT unique numbering for immunoglobulin and T cell receptor variable domains and Ig superfamily V-like domains".
Dev. Comp. Immunol., 27, 55-77 (2003) PMID: 12477501 LIGM:268

Citing the IMGT unique numbering for C-DOMAIN and C-LIKE-DOMAIN:
Lefranc, M.-P., Pommié, C., Kaas, Q., Duprat, E., Bosc, N., Guiraudou, D., Jean, C., Ruiz, M., Da Piedade, I., Rouard, M., Foulquier, E., Thouvenin, V. and Lefranc, G.
"IMGT unique numbering for immunoglobulin and T cell receptor constant domains and Ig superfamily C-like domains".
Dev. Comp. Immunol., 29, 185-203 (2005) PMID: 15572068 LIGM:293

Citing the IMGT unique numbering for G-DOMAIN and G-LIKE-DOMAIN
Lefranc M.-P., Duprat E., Kaas Q., Tranne M., Thiriot A. and Lefranc G. IMGT unique numbering for MHC groove G-DOMAIN and MHC superfamily (MhcSF) G-LIKE-DOMAIN. Dev. Comp. Immunol., 2005, 29, 917-938 PMID: 15936075