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.
Crystal structure of pig pancreatic alpha-amylase isoenzyme II, in complex with the carbohydrate inhibitor acarbose.,Gilles C, Astier JP, Marchis-Mouren G, Cambillau C, Payan F Eur J Biochem. 1996 Jun 1;238(2):561-9. PMID:8681972
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
↑ Gilles C, Astier JP, Marchis-Mouren G, Cambillau C, Payan F. Crystal structure of pig pancreatic alpha-amylase isoenzyme II, in complex with the carbohydrate inhibitor acarbose. Eur J Biochem. 1996 Jun 1;238(2):561-9. PMID:8681972