Table 2. Hydrogen-bond interactions (in Å) in the T (PDB entry 2hhb), R (PDB entry 1aj9) and Hb ζ2β2 s structures.
In structures with a tetramer in the asymmetric unit, the contact distances shown are between the α1–β2 (ζ1–βs2) interface or β1–β1 or α1–α1 (ζ1–ζ2). Corresponding contact distances were also observed at the symmetry-related dimer interfaces. Similar contact interactions were also obtained when PDB entries 2dn2 (T structure) or 1ljw (R structure) were used in the analysis.
| Hb ζ2β2 s | |||||
|---|---|---|---|---|---|
| Contact | T | R | ABCD | EFGH | |
| α1Thr38 OH | β2His97 O | — | 2.4 | — | — |
| α1Thr41 OH | β2His97 ND1 | — | — | — | — |
| α1Thr38 OH | β2Asp99 OD1 | — | — | — | — |
| α1Tyr42 OH | β2Asp99 OD1 | 2.5 | — | 2.4 | 2.4 |
| α1Asp94 OD2 | β2Asn102 ND2 | — | 3.2 | — | — |
| α1Asn97 ND2 | β2Asp99 OD1 | 2.8 | — | 2.9 | 2.8 |
| α1Leu91/Ile90 O | β2Arg40 NE | 2.8 | — | 3.4 | 2.8 |
| α1Arg92 O | β2Arg40 NE | 3.3 | — | — | — |
| α1Asp94 OD1 | β2Trp37 NE1 | 3.0 | 3.3 | — | — |
| β1His146 NE | β1Asp94 OD | 2.8 | — | 2.7 | 2.6 |
| β1His146 OT | α2Lys40 NZ | 2.5 | — | 2.7 | 2.7 |
| α1Arg141 NH2 | α2Asp126 OE | 2.7 | — | — | — |
| α1Arg141 OT | α2Lys127 NZ | 2.8 | — | — | — |
| α1Tyr140 OH | α1Val93 O | 2.7 | 2.8 | — | — |
| α1Arg141 NH | β2Trp37 NE | — | — | 3.3 | Disorder |
| α1Arg141 NH | α1Arg92 O | — | — | 3.4 | Disorder |
| α1Arg141 NH | α1Asp94 OD | — | — | 3.7 | Disorder |
| α1Glu138 OE1 | α1Arg92 NH2 | — | — | 3.2 | Disorder |