Table 2.
Structural Alignment and Proposed Function of the Active Site Residues of the Dehydratases/Hydratases in Table 1.a
| Enzyme | H-Bond to W3 | H-Bond to W3 | Catalytic Residue | BB H-Bond to Catalytic Residue | Oxyanion Holeb | H-Bond to W2 | H-Bond to W3 | H-Bond to W2c | H-Bond to Asp/Glu n-4 |
|---|---|---|---|---|---|---|---|---|---|
| Arrangement A DHs | |||||||||
| FabA | — | — | His70A (cis) | Val76A | Gly79A | Cys80A | — | Asp84B | Gln88B |
| PaFabZ | — | — | His49A (cis) | Ile55A | Gly58A | Val59A | His13B | Glu63B | Gln67B |
| PfFabZ | — | — | His133A (cis) | Ile139A | Gly142A | Val143A | His98B | Glu147B | Gln151B |
| HpFabZ | — | — | His58A (cis) | Ile64A | Gly67A | Val68A | His23B | Glu72B | Gln76B |
| CjFabZ | — | — | His48A (cis) | Ile54A | Gly57A | Val58A | His13B | Glu62B | Gln66B |
| DEBS DH | — | — | His2409 (trans) | Leu2416 | Gly2419 | Ser2420 | Tyr2533 | Asp2571 | Gln2575 |
| CurF DH | — | — | His1720 (trans) | Leu1727 | Ser1730 | Thr1731 | Tyr1851 | Asp1893 | Gln1897 |
| CurH DH | — | — | His971 (trans) | Val978 | Val982 | Ser983 | Tyr1094 | Asp1136 | Arg1140 |
| CurJ DH | — | — | His978 (trans) | Val985 | Gly988 | Ala989 | (Leu1115) | Asp1156 | Gln1160 |
| CurK DH | — | — | His996 (trans) | Leu1003 | Ala1006 | Thr1007 | Tyr1127 | Asp1169 | Gln1173 |
| FAS DH | — | — | His878 (trans) | Leu885 | Gly888 | Thr889 | Tyr1003 | Asp1033 | His1037 |
|
| |||||||||
| Arrangement J DHs & Hydratases | |||||||||
| TlFAS DH | Asp1586 | Asn1588 | His1591 (trans) | Ile1606 | Gly1609 | Met1610 | — | H2O* | — |
| ScFAS DH | Asp1559 | Asn1561 | His1564 (trans) | Ile1579 | Gly1582 | Met1583 | — | H2O* | — |
| PhaJ | Asp31A | Asn33A | His36A (trans) | Ile51A | Gly54A | Met55A | — | Ser62B | — |
| CtMFE-2 Hydratase 2 | Asp808 | Asn810 | His813 (trans) | Ile828 | Gly831 | Met832 | — | H2O | — |
| HsMFE-2 Hydratase 2 | Asp510 | Asn512 | His515 (trans) | Ile530 | Gly533 | Leu534 | — | H2O* | — |
| DmMFE-2 Hydratase 2 | Asp496 | Asn498 | His501 (trans) | Ile516 | Gly519 | Leu520 | — | H2O | — |
a
A or B after residue numbers indicates subunit for SHD enzymes/domains. Bold font indicates fully conserved residues; italic font indicates similar residues. W2 and W3 are water molecules referred to in the text and shown in Figures 3, 4, and 6. Parentheses indicate that a residue is located at the same location as other residues in the same column but not sharing the same function. BB, backbone.
b
Positive end of helix αHD.
c
An asterisk indicates that a water was not present in the crystal structures but is assumed to be involved based on structural superimposition with PhaJ and the other MFE-2 hydratase 2s.