Table 2.
Water-amide proton exchange rates for HbCO A in the absence and presence of IHP. The measurements were carried out in 0.1 M sodium phosphate at pH 7.0 and 30 °C using a Bruker 800-MHz spectrometer. Reprinted with permission from ref. 74. Copyright 2013 American Chemical Society.
| residue | kex (s–1) without IHP | kex (s–1) with IHP | intrinsic kex (s–1)b |
|---|---|---|---|
| α5Ala | 15.7 ± 0.1 | 34.2 ± 1.0 | 15.0 |
| α20His | 2.6 ± 0.2 | 2.5 ± 0.1 | 43.7 |
| α22Gly | 34.7 ± 0.2 | 35.3 ± 0.6 | 48.6 |
| α38Thr | 38.3 ± 0.7 | 19.3 ± 0.8 | 12.8 |
| α45His | 5.4 ± 0.1 | 4.6 ± 0.4 | 25.1 |
| α50His | 60.3 ± 0.3 | 52.0 ± 0.8 | 87.2 |
| α51Gly | 43.7 ± 0.4 | 39.9 ± 0.6 | 119.0 |
| α52Ser | 2.3 ± 0.1 | 2.4 ± 0.1 | 90.5 |
| α53Ala | 63.1 ± 0.9 | 66.1 ± 0.5 | 52.1 |
| α54Gln | 6.1 ± 0.1 | 6.8 ± 0.2 | 30.0 |
| α74Asp | 3.7 ± 0.1 | 3.7 ± 0.1 | 9.5 |
| α82Ala | 35.6 ± 0.1 | 19.5 ± 0.2 | 52.1 |
| α115Ala | 11.1 ± 0.2 | 11.5 ± 0.3 | 15.0 |
| β3Leu | 4.3 ± 0.3 | 1.5 ± 0.1 | 16.8 |
| β6Glu | 3.7 ± 0.1 | 5.5 ± 0.4 | 4.7 |
| β19Asn | 4.8 ± 0.2 | 5.6 ± 0.1 | 58.4 |
| β41Phe | – a | 40.4 ± 2.0 | 24.9 |
| β44Ser | 28.8 ± 0.5 | 48.7 ± 0.7 | 43.5 |
| β47Asp | 4.2 ± 0.1 | 7.5 ± 0.2 | 17.3 |
| β52Asp | 1.3 ± 0.1 | 4.0 ± 0.2 | 7.6 |
| β78Leu | – a | 1.2 ± 0.1 | 16.8 |
| β79Asp | 6.4 ± 0.2 | 5.7 ± 0.1 | 10.2 |
| β81Leu | 59.6 ± 0.8 | 19.4 ± 0.8 | 14.3 |
| β82Lys | 14.8 ± 0.3 | – a | 14.7 |
| β87Thr | 16.9 ± 0.4 | 17.1 ± 0.3 | 22.2 |
| β120Lys | 5.2 ± 0.2 | 7.2 ± 0.4 | 35.2 |
a
Exchange rates of <1 s–1, which are undetectable.
b
Intrinsic exchange rates derived using SPHERE (http://www.fccc.edu/research/labs/roder/sphere/).