5GOR

Crystal structure of alkaline invertase InvA from Anabaena sp. PCC 7120

Summary for 5GOR

• Entry DOI: 10.2210/pdb5gor/pdb
• Related: 5GOO 5GOP 5GOQ
• Descriptor: Alkaline Invertase, GLYCEROL, SULFATE ION, ... (4 entities in total)
• Functional Keywords: alkaline invertases, cyanobacteria, glycoside hydrolase family 100, sucrose hydrolysis, hydrolase
• Biological source: Nostoc sp. PCC 7120
• Total number of polymer chains: 6
• Total formula weight: 325993.47

Authors

Xie, J.,Cai, K.,Hu, H.X.,Jiang, Y.L.,Yang, F.,Hu, P.F.,Chen, Y.,Zhou, C.Z. (deposition date: 2016-07-28, release date: 2016-11-02, Last modification date: 2023-11-08)

Primary citation

Xie, J.,Cai, K.,Hu, H.X.,Jiang, Y.L.,Yang, F.,Hu, P.F.,Cao, D.D.,Li, W.F.,Chen, Y.,Zhou, C.Z.
Structural Analysis of the Catalytic Mechanism and Substrate Specificity of Anabaena Alkaline Invertase InvA Reveals a Novel Glucosidase
J. Biol. Chem., 291:25667-25677, 2016

PubMed Abstract: Invertases catalyze the hydrolysis of sucrose to glucose and fructose, thereby playing a key role in primary metabolism and plant development. According to the optimum pH, invertases are classified into acid invertases (Ac-Invs) and alkaline/neutral invertases (A/N-Invs), which share no sequence homology. Compared with Ac-Invs that have been extensively studied, the structure and catalytic mechanism of A/N-Invs remain unknown. Here we report the crystal structures of Anabaena alkaline invertase InvA, which was proposed to be the ancestor of modern plant A/N-Invs. These structures are the first in the GH100 family. InvA exists as a hexamer in both crystal and solution. Each subunit consists of an (α/α) barrel core structure in addition to an insertion of three helices. A couple of structures in complex with the substrate or products enabled us to assign the subsites -1 and +1 specifically binding glucose and fructose, respectively. Structural comparison combined with enzymatic assays indicated that Asp-188 and Glu-414 are putative catalytic residues. Further analysis of the substrate binding pocket demonstrated that InvA possesses a stringent substrate specificity toward the α1,2-glycosidic bond of sucrose. Together, we suggest that InvA and homologs represent a novel family of glucosidases.

PubMed: 27777307
DOI: 10.1074/jbc.M116.759290

Experimental method

X-RAY DIFFRACTION (2.673 Å)