Expression of starch-binding factor CBM20 in barley plastids controls the number of starch granules and the level of CO2 fixation

Zhong, Yingxin; Sagnelli, Domenico; Topbjerg, Henrik Bak; Hasler-Sheetal, Harald; Andrzejczak, Olga; Hooshmand, Kourosh; Gislum, René; Jiang, Dong; Blennow, Andreas; Hebelstrup, Kim H.

doi:10.1093/jxb/erz401

Cited by 3 publications

(2 citation statements)

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“…The signal sequence was retrieved from A. niger glucoamylase (glaA), as this was shown to be a versatile secretion signal [ 39 ]. Additionally, the CBM20 domain was also retrieved from A. niger glucoamylase, representing a well and extensively studied enzyme containing a CBM20 [ 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 ]. The GH13 catalytic domain was derived from the well-known GH13 α-amylase from A. niger CBS 513.88, of which the accurately annotated genome sequence was available [ 48 ].…”

Section: Resultsmentioning

confidence: 99%

Novel Design of an α-Amylase with an N-Terminal CBM20 in Aspergillus niger Improves Binding and Processing of a Broad Range of Starches

et al. 2023

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In the starch processing industry including the food and pharmaceutical industries, α-amylase is an important enzyme that hydrolyses the α-1,4 glycosidic bonds in starch, producing shorter maltooligosaccharides. In plants, starch molecules are organised in granules that are very compact and rigid. The level of starch granule rigidity affects resistance towards enzymatic hydrolysis, resulting in inefficient starch degradation by industrially available α-amylases. In an approach to enhance starch hydrolysis, the domain architecture of a Glycoside Hydrolase (GH) family 13 α-amylase from Aspergillus niger was engineered. In all fungal GH13 α-amylases that carry a carbohydrate binding domain (CBM), these modules are of the CBM20 family and are located at the C-terminus of the α-amylase domain. To explore the role of the domain order, a new GH13 gene encoding an N-terminal CBM20 domain was designed and found to be fully functional. The starch binding capacity and enzymatic activity of N-terminal CBM20 α-amylase was found to be superior to that of native GH13 without CBM20. Based on the kinetic parameters, the engineered N-terminal CBM20 variant displayed surpassing activity rates compared to the C-terminal CBM20 version for the degradation on a wide range of starches, including the more resistant raw potato starch for which it exhibits a two-fold higher Vmax underscoring the potential of domain engineering for these carbohydrate active enzymes.

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Section: Resultsmentioning

confidence: 99%

Novel Design of an α-Amylase with an N-Terminal CBM20 in Aspergillus niger Improves Binding and Processing of a Broad Range of Starches

et al. 2023

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“…Elongated MOSs with DP > 7, constrained into the granule, finally become long amylose chains ( Denyer et al, 2001 ). Among the starch synthases, GBSSI takes on several exceptions: it is deficient in a Carbohydrate-Binding Module (CBM) in its structure; it is internalized within the granule and acts through a processive mode ( Hebelstrup et al, 2017 ; Zhong et al, 2020 ). Putting together these considerations have helped to theorize that GBSSI acts in the interior of the granule where amylose remains protected by hydrolytic enzymes of the stroma ( Seung, 2020 ); moreover, it may be that, in the absence of the amylopectin-environment, amylose would arrange in an insoluble compound, thus hindering its synthesis.…”

Section: Starch Biosynthesismentioning

confidence: 99%

The Triple Jags of Dietary Fibers in Cereals: How Biotechnology Is Longing for High FiberGrains

Botticella¹,

Savatin²,

Sestili³

2021

Front. Plant Sci.

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Cereals represent an important source of beneficial compounds for human health, such as macro- and micronutrients, vitamins, and bioactive molecules. Generally, the consumption of whole-grain products is associated with significant health benefits, due to the elevated amount of dietary fiber (DF). However, the consumption of whole-grain foods is still modest compared to more refined products. In this sense, it is worth focusing on the increase of DF fractions inside the inner compartment of the seed, the endosperm, which represents the main part of the derived flour. The main components of the grain fiber are arabinoxylan (AX), β-glucan (βG), and resistant starch (RS). These three components are differently distributed in grains, however, all of them are represented in the endosperm. AX and βG, classified as non-starch polysaccharides (NSP), are in cell walls, whereas, RS is in the endosperm, being a starch fraction. As the chemical structure of DFs influences their digestibility, the identification of key actors involved in their metabolism can pave the way to improve their function in human health. Here, we reviewed the main achievements of plant biotechnologies in DFs manipulation in cereals, highlighting new genetic targets to be exploited, and main issues to face to increase the potential of cereals in fighting malnutrition.

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Barley Carbohydrates as a Sustainable and Healthy Food Ingredient

Vaio

Cahú

Marchesano

et al. 2023

Sustainable Food Science - A Comprehensive Approach

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Expression of starch-binding factor CBM20 in barley plastids controls the number of starch granules and the level of CO2 fixation

Abstract: Interference in protein–starch interactions in barley by the expression of an exogenous high-affinity starch-binding factor (Carbohydrate-Binding Motif 20, CBM20) reveals a link between starch granule biosynthesis and the level of photosynthesis.

Cited by 3 publications

References 43 publications

Novel Design of an α-Amylase with an N-Terminal CBM20 in Aspergillus niger Improves Binding and Processing of a Broad Range of Starches

Novel Design of an α-Amylase with an N-Terminal CBM20 in Aspergillus niger Improves Binding and Processing of a Broad Range of Starches

The Triple Jags of Dietary Fibers in Cereals: How Biotechnology Is Longing for High FiberGrains

Barley Carbohydrates as a Sustainable and Healthy Food Ingredient

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