PDBsum entry 1mw2

Transferase

PDB id: 1mw2

Contents

Protein chain

628 a.a. *

Ligands

GLC-GLC-GLC-GLC

GLC-FRU

TRS

Waters ×429

* Residue conservation analysis

PDB id:

1mw2

Name:

Transferase

Title:

Amylosucrase soaked with 100mm sucrose

Structure:

Amylosucrase. Chain: a. Engineered: yes

Source:

Neisseria polysaccharea. Organism_taxid: 489. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.10Å R-factor: 0.205 R-free: 0.226

Authors:

L.K.Skov,O.Mirza,D.Sprogoe,I.Dar,M.Remaud-Simeon,C.Albenne,P.Monsan, M.Gajhede

Key ref:

L.K.Skov et al. (2002). Oligosaccharide and sucrose complexes of amylosucrase. Structural implications for the polymerase activity. J Biol Chem, 277, 47741-47747. PubMed id: 12364331 DOI: 10.1074/jbc.M207860200

Date:

27-Sep-02 Release date: 18-Dec-02

Protein chain

Q9ZEU2  (AMYS_NEIPO) -  Amylosucrase from Neisseria polysaccharea

Seq: 636 a.a.

Struc: 628 a.a.*

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

Enzyme reactions

• Enzyme class: E.C.2.4.1.4 - amylosucrase.
• Reaction: [(1->4)-alpha-D-glucosyl](n) + sucrose = [(1->4)-alpha-D-glucosyl](n+1) + D-fructose

[(1->4)-alpha-D-glucosyl](n) + sucrose = [(1->4)-alpha-D-glucosyl](n+1) + D-fructose (Bound ligand (Het Group name = GLC) corresponds exactly)

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

Added reference

DOI no: 10.1074/jbc.M207860200

J Biol Chem 277:47741-47747 (2002)

PubMed id: 12364331

Oligosaccharide and sucrose complexes of amylosucrase. Structural implications for the polymerase activity.

L.K.Skov, O.Mirza, D.Sprogøe, I.Dar, M.Remaud-Simeon, C.Albenne, P.Monsan, M.Gajhede.

ABSTRACT

The glucosyltransferase amylosucrase is structurally quite similar to the hydrolase alpha-amylase. How this switch in functionality is achieved is an important and fundamental question. The inactive E328Q amylosucrase variant has been co-crystallized with maltoheptaose, and the structure was determined by x-ray crystallography to 2.2 A resolution, revealing a maltoheptaose binding site in the B'-domain somewhat distant from the active site. Additional soaking of these crystals with maltoheptaose resulted in replacement of Tris in the active site with maltoheptaose, allowing the mapping of the -1 to +5 binding subsites. Crystals of amylosucrase were soaked with sucrose at different concentrations. The structures at approximately 2.1 A resolution revealed three new binding sites of different affinity. The highest affinity binding site is close to the active site but is not in the previously identified substrate access channel. Allosteric regulation seems necessary to facilitate access from this binding site. The structures show the pivotal role of the B'-domain in the transferase reaction. Based on these observations, an extension of the hydrolase reaction mechanism valid for this enzyme can be proposed. In this mechanism, the glycogen-like polymer is bound in the widest access channel to the active site. The polymer binding introduces structural changes that allow sucrose to migrate from its binding site into the active site and displace the polymer.

Selected figure(s)

Figure 1.
Fig. 1. Stereo picture illustrating the various sucrose- and oligosaccharide binding sites on amylosucrase. The three oligosacchararide binding sites are labeled OB1, OB2, and OB3. Sucrose at the surface site is colored magenta and labeled SB2. The B'-domain is colored yellow.

Figure 5.
Fig. 5. Schematic representation of the interactions at the AS·sucrose binding site (SB2).

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2002, 277, 47741-47747) copyright 2002.

Figures were selected by an automated process.