Nucleotide sequence and X-ray structure of cyclodextrin glycosyltransferase from Bacillus circulans strain 251 in a maltose-dependent crystal form.
Lawson, C.L., van Montfort, R., Strokopytov, B., Rozeboom, H.J., Kalk, K.H., de Vries, G.E., Penninga, D., Dijkhuizen, L., Dijkstra, B.W.(1994) J Mol Biol 236: 590-600
- PubMed: 8107143 
- DOI: https://doi.org/10.1006/jmbi.1994.1168
- Primary Citation of Related Structures:  
1CDG - PubMed Abstract: 
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.
Organizational Affiliation: 
Laboratory of Biophysical Chemistry, University of Groningen, The Netherlands.