PMID: 8681972 , Related PDB ids: 105E, T8357

Authors:

Gilles C, Astier JP, Marchis-Mouren G, Cambillau C, Payan F

Title:

Crystal structure of pig pancreatic alpha-amylase isoenzyme II, in complex with the carbohydrate inhibitor acarbose.

Journal:

Eur J Biochem. 1996 Jun 1;238(2):561-9.

Abstract:

Two different crystal forms of pig pancreatic alpha-amylase isoenzyme II (PPAII), free and complexed to a carbohydrate inhibitor (acarbose), have been compared together and to previously reported structures of PPAI. A crystal form obtained at 4 degrees C, containing nearly 72% solvent, made it possible to obtain a new complex with acarbose, different from a previous one obtained at 20 degrees C [Qian, M., Buisson, G., Duee, E., Haser, H. & Payan, F. (1994) Biochemistry 33, 6284-6294]. In the present form, six contiguous subsites of the enzyme active site are occupied by the carbohydrate ligand; the structural data indicate that the binding site is capable of holding more than the five glucose units of the scheme proposed through kinetic studies. A monosaccharide ring bridging two protein molecules related by the crystal packing is located on the surface, at a distance of 2.0 nm from the reducing end of the inhibitor ligand; the symmetry-related glucose ring in the crystal lattice is found 1.5 nm away from the non-reducing end of the inhibitor ligand.