Lysines and cysteines of the Homo sapiens IGHG1, IGKC and IGLC1 and positions in the C-DOMAIN

Citing this table: Lefranc, M.-P. and Lefranc, G., The Immunoglobulin FactsBook, Academic Press, London, UK (458 pages), 2001, ISBN:012441351X

1. Structural and biological properties of human immunoglobulins

2. Human immunoglobulin (IG) chain characteristics

3. IG interchain disulfide bridges per monomer

5. Amino acid positions involved in ADCC, ADCP, CDC, half-life and half-IG exchange

6. IMGT engineered variant nomenclature: IGHG variants

7. Homo sapiens IGHG1 amino acids involved in the interactions with the C1q, FcγR and FCGRT

C-DOMAIN strands, turns and loops IMGT positions Homo sapiens IGHG1 Homo sapiens IGKC Homo sapiens IGLC1
A-STRAND 1.5-15 K1.1
K12 K12
B-STRAND 16-26 K16
C23 C23 C23 C23 C23
BC-LOOP 27-38 K38 K38
C-STRAND 39-45 W41 W41 W41 W41 W41
K42 K42
CD-STRAND 45.1-45.5 K45.4
D-STRAND 77-84 K79 K79
DE-TURN 84.1-85.1 K84.1
N84.4 K84.4
E-STRAND 85-93 K88
V89 L89 L89 L89 L89
K93 K93
F-STRAND 97-104 K97
K100 K100
C104 C104 C104 C104 C104
FG-LOOP 105-117 K105
K109 K109
G-STRAND 118-127 D118 E118 Q118 T118 E118
K119 K119 K119 K119 K119
CHS K130
Nb of lysines 6 12 7 8 9

Positions are according to the IMGT unique numbering for C-DOMAIN [1]. For correspondence between the IMGT unique numbering with other numberings, see Correspondence between C numberings.

Sequences are from Homo sapiens IGHG1*01 (J00228), Homo sapiens IGKC*01 (J00241) and Homo sapiens IGLC1*02 (X51755).

In addition to the lysines are shown:
- the five characteristic amino acids of a C-DOMAIN [2,3]. Four of them are highly conserved and hydrophobic [4] and are common to the V domain: C23 (1st-CYS), W41 (CONSERVED-TRP), 89 (hydrophobic) and C104 (2nd-CYS) [5]. These four amino acids contribute to the two major features shared by the V and C domains: the disulfide bridge (between the two cysteines 23 and 104) and the internal hydrophobic core of the domain (with the side chains of tryptophan W41 and amino acid 89) [2,3]. The fifth position, 118 is diverse in the C-DOMAIN and is characterized as being an FG loop anchor (whereas it is conserved in the V-DOMAIN and represented by J-PHE 118 or J-TRP 118).
- the CH2 N84.4 site of N-glycosylation (IMGT Lexique Glycosylation) at the top of the DE turn. The asparagine N84.4 is part of a N-glycosylation motif NXS/T (NST in Homo sapiens IGHG1).

[1] 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 pdf with permission from Elsevier.
[2] Lefranc, M-P. Immunoglobulin (IG) and T cell receptor genes (TR): IMGT® and the birth and rise of immunoinformatics. Front Immunol. 2014 Feb 05;5:22. doi: 10.3389/fimmu.2014.00022. Open access. PMID: 24600447.
[3] Lefranc, M-P. Immunoglobulins: 25 years of Immunoinformatics and IMGT-ONTOLOGY. Biomolecules. 2014, 4(4), 1102-1139; doi:10.3390/biom4041102. Open access. PMID: 25521638.
[4] Pommié, C., Levadoux, S., Sabatier, R., Lefranc, G. and Lefranc, M.-P. IMGT standardized criteria for statistical analysis of immunoglobulin V-REGION amino acid properties J. Mol. Recognit., 17, 17-32 (2004). PMID: 14872534 pdf.
[5] 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 pdf with permission from Elsevier.
CNRS Université de Montpellier European Commission

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