Crystal structure and insights into the oligomeric state of UDP-glucose pyrophosphorylase from sugarcane.

Camila A Cotrim,Bostjan Kobe,Jose Sergio M Soares,Marcelo Menossi,Eugene A Permyakov

doi:10.1371/journal.pone.0193667

Camila A Cotrim, Bostjan Kobe + Show 3 more

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https://doi.org/10.1371/journal.pone.0193667

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Abstract

UDP-glucose pyrophosphorylase (UGPase) is found in all organisms and catalyses the formation of UDP-glucose. In sugarcane, UDP-glucose is a branch-point in the carbon channelling into other carbohydrates, such as sucrose and cellulose, which are the major factors for sugarcane productivity. In most plants, UGPase has been described to be enzymatically active in the monomeric form, while in human and yeast, homo-octamers represent the active form of the protein. Here, we present the crystal structure of UGPase from sugarcane (ScUGPase-1) at resolution of 2.0 Å. The crystals of ScUGPase-1 reveal the presence of two molecules in the asymmetric unit and the multi-angle light scattering analysis shows that ScUGPase-1 forms a mixture of species ranging from monomers to larger oligomers in solution, suggesting similarities with the orthologs from yeast and human.

Highlights

Sugarcane (Saccharum ssp. hybrids) is a highly productive C4 crop used for many centuries to produce sugar and, more recently, other value-added products such as ethanol and bioelectricity, through fermentation and burning of the sugarcane bagasse, respectively
UDP-glucose pyrophosphorylase (UGPase; EC 2.7.7.9) is important and essential in this carbon regulation, whereas the sugar, UDP-glucose, represents an important branch point in the C channel directing for synthesis of starch, sucrose or cellulose [2,3,4]
ScUGPase-1 was crystallized fused to an N-terminal His6-tag and TEV protease cleavage site, which added 32 residues to the chain (MHHHHHHGAGGCCPGCCGGGENLYFQGIITSL)

Summary

Introduction

Sugarcane (Saccharum ssp. hybrids) is a highly productive C4 crop used for many centuries to produce sugar and, more recently, other value-added products such as ethanol and bioelectricity, through fermentation and burning of the sugarcane bagasse, respectively. Thereby, the accumulation of sucrose in the culm and the bagasse, cellulosic biomass, are the major yield components [1]. The particular importance of biochemical factors in the regulation of carbon (C)-partitioning to sucrose accumulation in the culm and cellulose synthesis are crucial to improve the sugarcane yield capacity. UDP-glucose pyrophosphorylase (UGPase; EC 2.7.7.9) is important and essential in this carbon regulation, whereas the sugar, UDP-glucose, represents an important branch point in the C channel directing for synthesis of starch, sucrose or cellulose [2,3,4].

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