TABLE 1.
MALLS analysis of fibulin-4 and -5
Fibulin-4 and -5 were analyzed by MALLS to obtain details of their molecular masses in solution (for domain structures, see Fig. 1A). Without added CaCl2 (HBS buffer), F4 and nF4 were monomeric. In the presence of 0.5 mm CaCl2 (HBS+Ca buffer), apparent dimers predominated, and some larger aggregates were also detected (data not shown). Similarly, F5 was monomeric in HBS (below) but dimerized in HBS+Ca (data not shown).4 Fibulin-5 mutant F5S227P and fibulin-5 domain pairs were also monomeric in HBS. Calculated molecular masses from primary sequences (without carbohydrate) and SDS-PAGE-determined molecular masses are also shown.
| Molecule (buffer) | MALLS-measured molecular mass | SDS-PAGE-measured molecular mass | Calculated molecular mass |
|---|---|---|---|
| kDa | kDa | kDa | |
| F4 (HBS) monomer | 52 | 52 | 49 |
| nF4 (HBS) monomer | 30 | 40 | 27 |
| F4 (HBS+Ca) “dimer” | 94 | ||
| F4 (HBS+Ca) monomer | 56 | ||
| nF4 (HBS+Ca) “dimer” | 60 | ||
| nF4 (HBS+Ca) monomer | 31 | ||
| F5 (HBS) monomer | 51 | 53 | 50 |
| F5-S227P (HBS) monomer | 52 | ||
| F5-E1+2 (HBS) monomer | 20 | 25 | 14 |
| F5-E2+3 (HBS) monomer | 13 | 15 | 9 |
| F5-E4+5 (HBS) monomer | 13 | 15 | 9 |
| F5-E5+6 (HBS) monomer | 16 | 18 | 10 |
| F5-E6FC (HBS) monomer | 24 | 30 | 19 |