1I75

CRYSTAL STRUCTURE OF CYCLODEXTRIN GLUCANOTRANSFERASE FROM ALKALOPHILIC BACILLUS SP.#1011 COMPLEXED WITH 1-DEOXYNOJIRIMYCIN

Summary for 1I75

• Entry DOI: 10.2210/pdb1i75/pdb
• Related: 1PAM
• Descriptor: CYCLODEXTRIN GLUCANOTRANSFERASE, CALCIUM ION, 1-DEOXYNOJIRIMYCIN, ... (4 entities in total)
• Functional Keywords: protein-inhibitor complex, transferase
• Biological source: Bacillus sp.
• Cellular location: Secreted : P05618
• Total number of polymer chains: 2
• Total formula weight: 151273.17

Authors

Kanai, R.,Haga, K.,Yamane, K.,Harata, K. (deposition date: 2001-03-08, release date: 2001-04-11, Last modification date: 2024-11-13)

Primary citation

Kanai, R.,Haga, K.,Yamane, K.,Harata, K.
Crystal structure of cyclodextrin glucanotransferase from alkalophilic Bacillus sp. 1011 complexed with 1-deoxynojirimycin at 2.0 A resolution.
J.Biochem.(Tokyo), 129:593-598, 2001

PubMed Abstract: 1-Deoxynojirimycin, a pseudo-monosaccharide, is a strong inhibitor of glucoamylase but a relatively weak inhibitor of cyclodextrin glucanotransferase (CGTase). To elucidate this difference, the crystal structure of the CGTase from alkalophilic Bacillus sp. 1011 complexed with 1-deoxynojirimycin was determined at 2.0 A resolution with the crystallographic R value of 0.154 (R(free) = 0.214). The asymmetric unit of the crystal contains two CGTase molecules and each molecule binds two 1-deoxynojirimycins. One 1-deoxynojirimycin molecule is bound to the active center by hydrogen bonds with catalytic residues and water molecules, but its binding mode differs from that expected in the substrate binding. Another 1-deoxynojirimycin found at the maltose-binding site 1 is bound to Asn-667 with a hydrogen bond and by stacking interaction with the indole moiety of Trp-662 of molecule 1 or Trp-616 of molecule 2. Comparison of this structure with that of the acarbose-CGTase complex suggested that the lack of stacking interaction with the aromatic side chain of Tyr-100 is responsible for the weak inhibition by 1-deoxynojirimycin of the enzymatic action of CGTase.

PubMed: 11275559

Experimental method

X-RAY DIFFRACTION (2 Å)