TABLE 2.
Digestion of peptide precursors by ERAP1 variants
The data represent the maximal combined digestion (%) of peptide species longer than the natural HLA-B27 ligands (sequences highlighted in boldface) resulting from digestion of the synthetic precursor by the indicated ERAP1 variant. It was calculated as follows: 100 − % combined yield of the corresponding species. The minimal and maximal values observed with the peptides tested with each variant are highlighted in boldface. The fully processed natural ligands RRYQKSTEL (peptide 9) and RRYQKSTELLIR (peptide 10) are not included. The data are means ± S.D. of at least three experiments.
| Peptide | Arg-528/Asp-575, % maximum | Lys-528/Asp-575, % maximum | Arg-528/Asn-575, % maximum | Lys-528/Asn-575, % maximum | Trimming scorea |
||
|---|---|---|---|---|---|---|---|
| Mean of F.R. | P1 | ||||||
| 1 | GRHHEAS.IRLPSQYNF | 15.0 ± 3.0 | 15.9 ± 2.5 | 34.7 ± 1.1 | 79.8 ± 9.2 | 1.6 | 2 |
| 2 | LGVFRKF.SRFPEALRL | 6.8 ± 1.2 | 36.5 ± 3.4 | 76.7 ± 6.9 | 95.1 ± 6.7 | 1.7 | 2 |
| 3 | NLKARNS.FRYNGLIHR | 48.4 ± 5.4 | 51.3 ± 2.4 | 63.7 ± 1.8 | 84.9 ± 1.7 | 2.0 | 2 |
| 4 | IMYKKRT.KRLVVFDAR | 29.6 ± 2.5 | 32.8 ± 0.1 | 29.9 ± 3.0 | 77 ± 2.7 | 2.0 | 1 |
| 5 | DVVYAL.KRQGRTLYGF | 10.5 ± 0.7 | 3.6 ± 0.5 | 24.6 ± 2.1 | 99.9 ± 0.5 | 2.5 | 1 |
| 6 | LYSESL.ARYGKSPYLY | 79.8 ± 0.3 | 72.8 ± 2.3 | 79.2 ± 4.1 | 77.9 ± 2.6 | 2.8 | 4 |
| 7 | LREI.RRYQKSTEL | 48 ± 1.2 | 59.3 ± 3.4 | 73.7 ± 1.8 | 74.5 ± 5.3 | 2.0 | 1 |
| 8 | LREI.RRYQKSTELLIR | 50.9 ± 5.8 | 61.2 ± 2.1 | 67.7 ± 0.8 | 85.5 ± 1.3 | 2.0 | 1 |
| Mean | 36.1 | 41.7 | 56.3 | 84.3 | |||
a Trimming susceptibility scores for each residue are based on relative cleavage efficiencies as determined in a previous study (13): score 1, 0–25% (T, H, Q, G, N, E, W, D, K, V, R, P); 2, 25–50% (F, I, S); 3, 50–75% (C); 4, 75–100% (A, L, M, Y). For each substrate the mean score of all the flanking residues (mean of F.R.) and the score of the N-terminal residue of the natural ligand (P1) are shown.