PDBsum entry 3wms

Transferase

PDB id: 3wms

Contents

Protein chain

685 a.a.

Metals

_CA ×2

Waters ×270

PDB id:

3wms

Name:

Transferase

Title:

The crystal structure of y195i mutant alpha-cyclodextrin glycosyltransferase from paenibacillus macerans

Structure:

Alpha-cyclodextrin glucanotransferase. Chain: a. Synonym: alpha-cyclodextrin glycosyltransferase, cyclodextrin- glycosyltransferase, cgtase. Engineered: yes. Mutation: yes

Source:

Paenibacillus macerans. Organism_taxid: 44252. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.30Å R-factor: 0.176 R-free: 0.221

Authors:

T.Xie,Y.J.Hou,D.F.Li,Y.Yue,S.J.Qian,Y.P.Chao

Key ref:

T.Xie et al. (2014). Structural basis of a mutant Y195I α-cyclodextrin glycosyltransferase with switched product specificity from α-cyclodextrin to β-/γ-cyclodextrin. J Biotechnol, 182, 92-96. PubMed id: 24637377 DOI: 10.1016/j.jbiotec.2014.03.014

Date:

24-Nov-13 Release date: 12-Nov-14

Protein chain

P04830  (CDGT1_PAEMA) -  Cyclomaltodextrin glucanotransferase from Paenibacillus macerans

Seq: 714 a.a.

Struc: 685 a.a.*

* PDB and UniProt seqs differ at 5 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.2.4.1.19 - cyclomaltodextrin glucanotransferase.
• Reaction: Degrades starch to cyclodextrins by formation of a 1,4-alpha-D- glucosidic bond.

DOI no: 10.1016/j.jbiotec.2014.03.014

J Biotechnol 182:92-96 (2014)

PubMed id: 24637377

Structural basis of a mutant Y195I α-cyclodextrin glycosyltransferase with switched product specificity from α-cyclodextrin to β-/γ-cyclodextrin.

T.Xie, Y.Hou, D.Li, Y.Yue, S.Qian, Y.Chao.

ABSTRACT

Cyclodextrin glycosyltransferase (EC 2.4.1.19) (CGTase) is an extracellular bacterial enzyme which has the unique capability of forming cyclodextrins from starch. Our previous investigation revealed that a mutant Y195I α-CGTase drastically altered the cyclodextrin specificity by switching toward the synthesis of both β- and γ-CDs (Xie et al., 2013a,b). In this study, we determined one X-ray structure of the mutant Y195I α-CGTase at 2.3Å. The overall structure was similar to that of the typical β-CGTase from Bacillus circulans 251, with minor difference in flexible domains since they showed about 70% homogeneity of amino acid sequences. The central site with isoleucine tended to be more flexible than tyrosine thus made the sugar chain, during the cyclization process, form a larger cyclodextrin like β- and γ-CDs surrounding the central site instead of α-CD. Superposition of the structure of Y195I α-CGTase with those of β-CGTase and γ-CGTase showed that residues Lys232, Lys89 and Arg177 at subsites +2, -3 and -7 could form smaller substrate binding cavity. In summary, the crystal structure revealed that moderate increase of mobility of the central site resulted in the switched product specificity from α-CD to β- and γ-CDs of the mutant Y195I α-CGTase. The space differences alongside the active domain may be another factor that impacts the product specificity of the CGTase.