Table 2.
Thermodynamic binding parameters for PDZ3 and neuroligin-1-based peptides determined by ITC.a
| peptide | Kd (μM) | ΔG (kcal/mol) | ΔH (kcal/mol) | TΔS (kcal/mol) | |
|---|---|---|---|---|---|
| 1 | b TTRV | — | — | — | — |
| 2 | c STTRV | 152 ± 3 | −5.0 ± 0.2 | −3.2 ± 0.1 | 1.8 ± 0.2 |
| 3 | HSTTRV | 21 ± 1 | −6.4 ± 0.1 | −6.5 ± 0.1 | −0.1 ± 0.1 |
| 4 | SHSTTRV | 18 ± 1 | −6.5 ± 0.1 | −7.1 ± 0.2 | −0.6 ± 0.2 |
| 5 | HSHSTTRV | 15 ± 1 | −6.6 ± 0.1 | −6.9 ± 0.1 | −0.3 ± 0.1 |
| 6 | PHSHSTTRV | 11 ± 1 | −6.8 ± 0.1 | −7.4 ± 0.1 | −0.6 ± 0.1 |
| 7 | HPHSHSTTRV | 10 ± 1 | −6.8 ± 0.1 | −8.9 ± 0.1 | −2.1 ± 0.1 |
a
Values are the arithmetic mean of at least two independent experiments. All c values measured between 1 and 9. Stoichiometric (n) values ranged from 0.92 to 1.15.
b
Insufficient heat detected to determine binding parameters.
c
ITC was conducted as a competition experiment in which the displacement of preincubated STTRV was measured.