Download MendeleyStructure of the Alpha-1,6/Alpha-1,4-Specific Glucansucrase Gtfa from Lactobacillus Reuteri 121
Pijning, T., Vujicic-Zagar, A., Kralj, S., Dijkhuizen, L., Dijkstra, B.W.(2012) Acta Crystallogr Sect F Struct Biol Cryst Commun 68: 1448
- PubMed: 23192022
- DOI: https://doi.org/10.1107/S1744309112044168
- Primary Citation of Related Structures:
4AMC - 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.
Organizational Affiliation:
Laboratory of Biophysical Chemistry, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands.
