Table 1.
Side chain conformations of ligands bound to Leloir glycosyltransferasesa
| Enzyme Function | gg | gt | tg | Eclipsed | Total | H-bonding to O6 |
|---|---|---|---|---|---|---|
| α-Galactosyltransferase | - | 6 (5) | 2 (2) | - | 8 (7) | 8 (7) |
| β-Galactosyltransferase | - | - | 8 (3) | - | 8 (3) | 8 (3) |
| α-N-Acetyl Galactosaminyltransferase | 1 (−) | 2 (2) | 5 (2) | - | 8 (4) | 8 (4) |
| α-Glucosyltransferase | 30 (15) | 3 (3) | 1 (−) | 3 (1) | 39 (19)b | 37 (18) |
| β-Glucosyltransferase | 10 (6) | 1 (1) | 1 (1) | - | 12 (8) | 12 (8) |
| α-N-Acetyl Glucosaminyltransferase | 4 (2) | 1 (−) | 1 (−) | 1 (−) | 7 (2) | 6 (2) |
| β-N-Acetyl Glucosaminyltransferase | 10 (6) | 4 (3) | - | 2 (−) | 16 (9) | 14 (7) |
| α-N-Acetyl Hexosaminyltransferasec | 1 (−) | 1 (−) | - | - | 2 (−) | 2 (−) |
| α-Mannosyltransferase | - | - | 1 (−) | - | 1 (−) | 1 (−) |
| β-Mannosyltransferase | 2 (2) | - | - | - | 2 (2) | 2 (2) |
| α-Valeniolyltransferase | 1 (−) | 1 (1) | - | - | 2 (1) | 2 (1) |
| Heptosyltransferase | 2 (−) | - | - | - | 2 (−) | 2 (−) |
| α-Sialyltransferase | 9 (7) | - | 1 (−) | 1 (−) | 11 (7) | 7 (6) |
| Total | 70 (38) | 19 (15) | 20 (8) | 2 (−) | 118 (62) | 109 (58) |
a
Data are listed at the 2.50 Å cutoff, with those for the 2.00 Å cutoff given in parentheses
b
Two structures bear ambiguous side chain conformations
c
These enzymes act on both glucosides and galactosides