Table 1 Relative amino acid composition of three key dermal ECM proteins. Monomeric type I collagen ([α1(I)]2α2(I), accession numbers P02452 (α1) and P08123 (α2)) is rich in Gly and Pro but contains few UV-B chromophores (Cys, His, Phe, Trp and Tyr). In contrast, fibronectin, (accession number P02751) and in particular fibrillin-1 (accession number P35555), are rich in UV-B chromophores and in the case of Fibrillin-1 Cys residues [9].
Amino Acid | Collagen I (%) | Fibronectin (%) | Fibrillin-1 (%) |
|---|---|---|---|
Ala (A) | 11.2 | 4.0 | 3.2 |
Arg (R) | 5.1 | 5.2 | 4.5 |
Asn (n) | 1.5 | 4.2 | 6.6 |
Asp (D) | 2.8 | 5.1 | 6.0 |
Cys (C) | 0.0 | 2.6 | 12.7 |
Gln (Q) | 2.6 | 5.5 | 3.6 |
Glu (E) | 4.6 | 5.9 | 7.0 |
Gly (G) | 33.1 | 8.2 | 10.7 |
His (H) | 0.6 | 2.2 | 1.7 |
IIe (I) | 1.0 | 4.7 | 5.2 |
Leu (L) | 2.4 | 5.2 | 4.8 |
Lys (K) | 3.4 | 3.2 | 3.9 |
Met (M) | 0.6 | 1.1 | 1.8 |
Phe (F) | 1.3 | 2.2 | 2.9 |
Pro (P) | 21.8 | 7.9 | 6.2 |
Ser (S) | 3.5 | 8.0 | 6.0 |
Thr (T) | 1.7 | 10.8 | 5.8 |
Trp (W) | 0.0 | 1.7 | 0.5 |
Tyr (Y) | 0.3 | 4.2 | 3.3 |
Val (V) | 2.6 | 8.0 | 3.8 |
Total chromophore content (%) | 2.2 | 12.9 | 21.1 |