TABLE 5.
A17 binding specificity of A27 mutants in PBS buffer at pH 6.5 by HSQC
The A27 mutants/A17 binding specificity were determined by HSQC spectroscopy, in which A17 fragment is uniformly 15N isotope-labeled, see text for details.
| A27 mutants | Mutation position | α-Helical contenta | F1 binding | F2 binding |
|---|---|---|---|---|
| A27-V78Ab | g | 93.0 | ++ | ++ |
| A27-F80A | b | 85.5 | + | + |
| A27-R81A | c | 89.0 | + | − |
| A27-N84A | f | 83.0 | + | − |
| A27-E87A | b | 95.8 | + | − |
| A27-T88A | c | 85.5 | − | − |
| A27-I94A | b | 89.3 | − | − |
| A27-S95A | c | 82.7 | − | − |
| A27-K98A | f | 91.9 | − | − |
| A27-K99A | g | 84.3 | − | − |
| A27-E87A,I94A | b | 89.7 | − | − |
| A27-V102Ab | c | 94.3 | ++ | ++ |
a The α-helical contents determined by CD spectroscopy were referred to in the α-helical content in parental A27(21–110) as 100% (Fig. 4A).
b In these A27 mutants, A27-V78A and -V102A, in which the mutation was beyond the A17 active binding sites (residues 80–100), were treated as negative controls.