Figure 11-17

(NAG)6 substrate:
Click on structure and drag to rotate. Click on figure to reset.

X-ray structure of HEW lysozyme in complex with (NAG)6. The protein is drawn in worm form colored in rainbow order from its N-terminus (blue) to its C-terminus (red) embedded in its transparent molecular surface (gray). The (NAG)6, which is drawn in stick form with its sugar residues designated A, at its nonreducing end, through F, at its reducing end, binds in a deep cleft in the enzyme surface. Rings A, B, and C (colored according to atom type with C green, N blue, and O red) are observed in the X-ray structure of the complex of (NAG)3 with lysozyme; the positions of rings D, E, and F (C cyan, N blue, O red) were inferred by model building. The side chains of lysozyme's active site residues, Glu 35 and Asp 52, which are drawn in space-filling form (C yellow, O red), catalyze the hydrolysis of the glycosidic bond between rings D and E. [Based on an X-ray structure by David Phillips, Oxford University. PDBid 1HEW.]