Nucleotide sequence and X-ray structure of cyclodextrin glycosyltransferase from Bacillus circulans strain 251 in a maltose-dependent crystal form.
The cyclodextrin glycosyltransferase (CGTase, EC 2.4.1.19) gene from Bacillus circulans strain 251 was cloned and sequenced. It was found to code for a mature protein of 686 amino acid residues, showing 75% identity to the CGTase from B. circulans strain 8. The X-ray structure of the CGTase was elucidated in a maltodextrin-dependent crystal form and refined against X-ray diffraction data to 2.0 A resolution. The structure of the enzyme is nearly identical to the CGTase from B. circulans strain 8. Three maltose binding sites are observed at the protein surface, two in domain E and one in domain C. The maltose-dependence of CGTase crystallization can be ascribed to the proximity of two of the maltose binding sites to intermolecular crystal contacts. The maltose molecules bound in the E domain interact with several residues implicated in a raw starch binding motif conserved among a diverse group of starch converting enzymes.
Lawson
C L
CL
Laboratory of Biophysical Chemistry, University of Groningen, The Netherlands.
van Montfort
R
R
Strokopytov
B
B
Rozeboom
H J
HJ
Kalk
K H
KH
de Vries
G E
GE
Penninga
D
D
Dijkhuizen
L
L
Dijkstra
B W
BW
D000595:Amino Acid Sequence; D001407:Bacillus / Q000201:enzymology*; D001483:Base Sequence; D001665:Binding Sites; D002240:Carbohydrate Sequence; D003001:Cloning, Molecular; D003196:Computer Graphics; D004269:DNA, Bacterial; D005964:Glucosyltransferases / Q000737:chemistry / Q000235:genetics*; D008320:Maltose / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D014961:X-Ray Diffraction
D004269:DNA, Bacterial; D008320:Maltose; D005964:Glucosyltransferases; C019963:cyclomaltodextrin glucanotransferase