Reaction: formation of a linear isomalto/malto-polysaccharide from linear malto-oligosaccharides
Other name(s): gtfB (gene name) (ambiguous); gtfC (gene name)
Systematic name: linear (1→4)-α-D-glucan:(1→4)/(1→6)-α-D-glucan 6-α-D-glucosyltransferase
Comments: The enzyme, originally discovered in lactic acid bacteria but later found in other organisms, is similar to EC 2.4.1.395, reuteransucrase, yet is not able to act on sucrose. The enzyme, which belongs to the glycoside hydrolase 70 (GH70) family, possesses both hydrolase and transglycosylase activities, cleaving α(1→4) linkages from the non-reducing end of linear maltooligosaccharides and synthesizing linear α(1→6)-glucan chains. It also possesses an endo-α(1→4)-glycosidase activity. Due to its narrow binding groove, it is not able to act on branched substrates. cf. EC 2.4.1.396, 4,6-α-glucanotransferase (linear and branched substrates, branched products).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:
References:
1. Kralj, S., van Geel-Schutten, G.H., Dondorff, M.MG., Kirsanovs, S., van der Maarel, M.JE.C. and Dijkhuizen, L. Glucan synthesis in the genus Lactobacillus: isolation and characterization of glucansucrase genes, enzymes and glucan products from six different strains. Microbiology (Reading) 150 (2004) 3681-3690. [PMID: 15528655]
2. Kralj, S., Grijpstra, P., van Leeuwen, S.S., Leemhuis, H., Dobruchowska, J.M., van der Kaaij, R.M., Malik, A., Oetari, A., Kamerling, J.P. and Dijkhuizen, L. 4,6-α-glucanotransferase, a novel enzyme that structurally and functionally provides an evolutionary link between glycoside hydrolase enzyme families 13 and 70. Appl. Environ. Microbiol. 77 (2011) 8154-8163. [PMID: 21948833]
3. Dobruchowska, J.M., Gerwig, G.J., Kralj, S., Grijpstra, P., Leemhuis, H., Dijkhuizen, L. and Kamerling, J.P. Structural characterization of linear isomalto-/malto-oligomer products synthesized by the novel GTFB 4,6-α-glucanotransferase enzyme from Lactobacillus reuteri 121. Glycobiology 22 (2012) 517-528. [PMID: 22138321]
4. Leemhuis, H., Dijkman, W.P., Dobruchowska, J.M., Pijning, T., Grijpstra, P., Kralj, S., Kamerling, J.P. and Dijkhuizen, L. 4,6-α-Glucanotransferase activity occurs more widespread in Lactobacillus strains and constitutes a separate GH70 subfamily. Appl. Microbiol. Biotechnol. 97 (2013) 181-193. [PMID: 22361861]
5. Gangoiti, J., Pijning, T. and Dijkhuizen, L. The Exiguobacterium sibiricum 255-15 GtfC enzyme represents a novel glycoside hydrolase 70 subfamily of 4,6-α-glucanotransferase enzymes. Appl. Environ. Microbiol. 82 (2016) 756-766. [PMID: 26590275]
6. Bai, Y., Gangoiti, J., Dijkstra, B.W., Dijkhuizen, L. and Pijning, T. Crystal structure of 4,6-α-glucanotransferase supports diet-driven evolution of GH70 enzymes from α-amylases in oral bacteria. Structure 25 (2017) 231-242. [PMID: 28065507]
7. Te Poele, E.M., van der Hoek, S.E., Chatziioannou, A.C., Gerwig, G.J., Duisterwinkel, W.J., Oudhuis, L.AA.CM., Gangoiti, J., Dijkhuizen, L. and Leemhuis, H. GtfC enzyme of Geobacillus sp. 12AMOR1 represents a novel thermostable type of GH70 4,6-α-glucanotransferase that synthesizes a linear alternating (α1→6)/(α1→4) α-glucan and delays bread staling. J. Agric. Food Chem. 69 (2021) 9859-9868. [PMID: 34427087]