4AMC

Crystal structure of Lactobacillus reuteri 121 N-terminally truncated glucansucrase GTFA

Summary for 4AMC

• Entry DOI: 10.2210/pdb4amc/pdb
• Descriptor: GLUCANSUCRASE, CALCIUM ION (2 entities in total)
• Functional Keywords: transferase, glycosyltransferase, reuteransucrase
• Biological source: LACTOBACILLUS REUTERI
• Total number of polymer chains: 1
• Total formula weight: 118085.46

Authors

Pijning, T.,Vujicic-Zagar, A.,Kralj, S.,Dijkhuizen, L.,Dijkstra, B.W. (deposition date: 2012-03-08, release date: 2012-11-07, Last modification date: 2023-12-20)

Primary citation

Pijning, T.,Vujicic-Zagar, A.,Kralj, S.,Dijkhuizen, L.,Dijkstra, B.W.
Structure of the Alpha-1,6/Alpha-1,4-Specific Glucansucrase Gtfa from Lactobacillus Reuteri 121
Acta Crystallogr.,Sect.F, 68:1448-, 2012

PubMed Abstract: The reuteransucrase GTFA from Lactobacillus reuteri 121, which belongs to glycosyl hydrolase family GH70, synthesizes branched α-glucans with both α-1,6- and α-1,4-glycosidic linkages (reuteran) from sucrose. The crystal structure of GTFA-ΔN, a 118 kDa fragment of GTFA comprising residues 745-1763 and including the catalytic domain, was determined at 3.6 Å resolution by molecular replacement. The crystals have large solvent channels and an unusually high solvent content of 85%. GTFA-ΔN has the same domain arrangement and domain topologies as observed in previously determined GH70 glucansucrase structures. The architecture of the GTFA-ΔN active site and binding pocket confirms that glucansucrases have a conserved substrate specificity for sucrose. However, this first crystal structure of an α-1,6/α-1,4-specific glucansucrase shows that residues from conserved sequence motif IV (1128-1136 in GTFA-ΔN) contribute to the acceptor-binding subsites and that they display differences compared with other structurally characterized glucansucrases. In particular, the structure clarifies the importance of residues following the transition-state stabilizer for product specificity, and especially residue Asn1134, which is in a position to interact with sugar units in acceptor subsite +2.

PubMed: 23192022
DOI: 10.1107/S1744309112044168

Experimental method

X-RAY DIFFRACTION (3.6 Å)