Table 1.
V domain strands and loops, IMGT (IMGT®, the international ImMunoGeneTics information system®) positions and lengths, based on the IMGT unique numbering for V domain (V-DOMAIN and V-LIKE-DOMAIN) [6]. FR: framework; CDR: complementarity determining regions.
| V Domain Strands and Loops a | IMGT Positions | Lengths b | Characteristic Residue@Position c | V-DOMAIN FR-IMGT and CDR-IMGT |
|---|---|---|---|---|
| A-STRAND | 1–15 | 15 (14 if gap at 10) | FR1-IMGT | |
| B-STRAND | 16–26 | 11 | 1st-CYS 23 | |
| BC-LOOP | 27–38 | 12 (or less) | CDR1-IMGT | |
| C-STRAND | 39–46 | 8 | CONSERVED-TRP 41 | FR2-IMGT |
| C’-STRAND | 47–55 | 9 | ||
| C’C”-LOOP | 56–65 | 10 (or less) | CDR2-IMGT | |
| C”-STRAND | 66–74 | 9 (or 8 if gap at 73) | FR3-IMGT | |
| D-STRAND | 75–84 | 10 (or 8 if gaps at 81, 82) | ||
| E-STRAND | 85–96 | 12 | hydrophobic 89 | |
| F-STRAND | 97–104 | 8 | 2nd-CYS 104 | |
| FG-LOOP | 105–117 | 13 (or less, or more) | CDR3-IMGT | |
| G-STRAND | 118–128 | 11 (or 10) | V-DOMAIN J-PHE 118 or J-TRP 118 d | FR4-IMGT |
a IMGT® labels (concepts of description) are written in capital letters. b in number of amino acids (or codons). c Residue@Position is a IMGT® concept of numerotation that numbers the position of a given residue (or that of a conserved property amino acid class), based on the IMGT unique numbering. d In the IG and TR V-DOMAIN, the G-STRAND (or FR4-IMGT) is the C-terminal part of the J-REGION, with J-PHE or J-TRP 118 and the canonical motif F/W-G-X-G (J-MOTIF) at positions 118–121.