PDBsum entry 4ays

Transferase

PDB id: 4ays

Contents

Protein chain

590 a.a.

PDB id:

4ays

Name:

Transferase

Title:

The structure of amylosucrase from d. Radiodurans

Structure:

Amylosucrase. Chain: a. Synonym: alpha-amylase. Engineered: yes

Source:

Deinococcus radiodurans. Organism_taxid: 1299. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

3.15Å R-factor: 0.202 R-free: 0.236

Authors:

L.K.Skov,S.Pizzut,M.Remaud-Simeon,M.Gajhede,O.Mirza

Key ref:

L.K.Skov et al. (2013). The structure of amylosucrase from Deinococcus radiodurans has an unusual open active-site topology. Acta Crystallogr Sect F Struct Biol Cryst Commun, 69, 973-978. PubMed id: 23989143 DOI: 10.1107/S1744309113021714

Date:

21-Jun-12 Release date: 11-Sep-13

Protein chain

Q9RVT9  (Q9RVT9_DEIRA) -  Alpha-amlyase from Deinococcus radiodurans (strain ATCC 13939 / DSM 20539 / JCM 16871 / CCUG 27074 / LMG 4051 / NBRC 15346 / NCIMB 9279 / VKM B-1422 / R1)

Seq: 644 a.a.

Struc: 590 a.a.

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

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

Added reference

DOI no: 10.1107/S1744309113021714

Acta Crystallogr Sect F Struct Biol Cryst Commun 69:973-978 (2013)

PubMed id: 23989143

The structure of amylosucrase from Deinococcus radiodurans has an unusual open active-site topology.

L.K.Skov, S.Pizzut-Serin, M.Remaud-Simeon, H.A.Ernst, M.Gajhede, O.Mirza.

ABSTRACT

Amylosucrases (ASes) catalyze the formation of an α-1,4-glucosidic linkage by transferring a glucosyl unit from sucrose onto an acceptor α-1,4-glucan. To date, several ligand-bound crystal structures of wild-type and mutant ASes from Neisseria polysaccharea and Deinococcus geothermalis have been solved. These structures all display a very similar overall conformation with a deep pocket leading to the site for transglucosylation, subsite -1. This has led to speculation on how sucrose enters the active site during glucan elongation. In contrast to previous studies, the AS structure from D. radiodurans presented here has a completely empty -1 subsite. This structure is strikingly different from other AS structures, as an active-site-lining loop comprising residues Leu214-Asn225 is found in a previously unobserved conformation. In addition, a large loop harbouring the conserved active-site residues Asp133 and Tyr136 is disordered. The result of the changed loop conformations is that the active-site topology is radically changed, leaving subsite -1 exposed and partially dismantled. This structure provides novel insights into the dynamics of ASes and comprises the first structural support for an elongation mechanism that involves considerable conformational changes to modulate accessibility to the sucrose-binding site and thereby allows successive cycles of glucosyl-moiety transfer to a growing glucan chain.