On the molecular structure of the amylopectin fraction isolated from “high-amylose” ae maize starches

Peymanpour, Ghazal; Marcone, Massimo F.; Ragaee, Sanaa; Tetlow, Ian J.; Lane, Christopher C.; Seetharaman, Koushik; Bertoft, Eric

doi:10.1016/j.ijbiomac.2016.06.029

Cited by 20 publications

(10 citation statements)

References 71 publications

(157 reference statements)

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“…A deficiency of either BEI or BEIIa results in no detectable or only small changes in endosperm starch phenotypes and kernel morphology in maize and rice ( Blauth et al, 2001 , 2002 ; Nakamura, 2002 ; Satoh et al, 2003 ; Yao et al, 2004 ). In contrast, a number of groups worldwide have reported on the specific impact of BEIIb on the fine structure, starch granule morphology, and starch physicochemical properties in endosperms from maize ( Yuan et al, 1993 ; Shi and Seib, 1995 ; Klucinec and Thompson, 2002 ; Yao et al, 2004 ; Li et al, 2007 ) and rice ( Nishi et al, 2001 ; Tanaka et al, 2004 ; Wei et al, 2010 ; Butardo et al, 2011 ; see also reviews by Wang et al, 2017 ; Nakamura, 2018 ).…”

Section: Resultsmentioning

confidence: 99%

Contributions of Three Starch Branching Enzyme Isozymes to the Fine Structure of Amylopectin in Rice Endosperm

2018

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Three starch branching enzyme (BE) isozymes, BEI, BEIIa, and BEIIb, are involved in starch biosynthesis in rice endosperm. Past in vivo and in vitro studies have suggested that each BE isozyme plays a distinct role in forming the fine structure of amylopectin. To elucidate more details of their roles, we prepared DNA constructs in which all the possible combinations of the expressions of these three isozymes were suppressed in developing rice endosperm. Analysis of the chain-length distributions of amylopectin produced under these various conditions confirmed the contributions of the individual BE isozymes to the fine structure of amylopectin in rice endosperm. Among these isozymes, the impact of loss of BEIIb activity on amylopectin fine structure was most remarkable and indicated that it plays a specific role in the synthesis of short chains with a 6–13 degree of polymerization (DP). The contribution of BEI to the amylopectin synthesis was unclear when only BEI activity was reduced. It was clear, however, when both BEI and BEIIb activities were substantially inhibited. The DP11-22 intermediate chains were markedly reduced in the ΔBEI/BEIIb line compared with the ΔBEIIb line, indicating that BEI plays a distinct role in the synthesis of these intermediate chains. Although no substantial change in amylopectin chain profile was detected in the ΔBEIIa line, the role of BEIIa could be deciphered by analyzing amylopectin fine structure from the ΔBEI/BEIIa/BEIIb line in comparison to that from ΔBEI/BEIIb line. This strongly suggests that BEIIa compensates for the role of BEI, rather than that of BEIIb, by forming intermediate chains of DP11-22. In addition, the new possibility that BEIIa is involved in the formation of starch granules in rice endosperm was suggested because the onset temperature for gelatinization of starch granules in the ΔBEIIa/BEIIb line was significantly higher than that in the ΔBEIIb line. In summary, the present study highlights the distinct roles of BEI, BEIIa, and BEIIb in the synthesis of amylopectin in developing rice endosperm.

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Section: Resultsmentioning

confidence: 99%

Contributions of Three Starch Branching Enzyme Isozymes to the Fine Structure of Amylopectin in Rice Endosperm

2018

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“…It is noted that the largest building blocks in group 6 contains as many chains as is found in a large part of the clusters. However, the chains in the building blocks are much shorter and the density of branches (DB) is higher (14~20%) [211,229,234,235,239] than in clusters (11~15%) [211,225,229,230,234,239] due to very short distances between the branches: ICL is only 1.4~2.3. The large clusters in cereals have typically 4-6 building blocks, whereas small clusters (many roots and tubers) contain 3~5 blocks on average (Table 3) [229].…”

Section: Branched Unitsmentioning

confidence: 99%

Understanding Starch Structure: Recent Progress

Bertoft¹

2017

Agronomy

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601

299

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Starch is a major food supply for humanity. It is produced in seeds, rhizomes, roots and tubers in the form of semi-crystalline granules with unique properties for each plant. Though the size and morphology of the granules is specific for each plant species, their internal structures have remarkably similar architecture, consisting of growth rings, blocklets, and crystalline and amorphous lamellae. The basic components of starch granules are two polyglucans, namely amylose and amylopectin. The molecular structure of amylose is comparatively simple as it consists of glucose residues connected through α-(1,4)-linkages to long chains with a few α-(1,6)-branches. Amylopectin, which is the major component, has the same basic structure, but it has considerably shorter chains and a lot of α-(1,6)-branches. This results in a very complex, three-dimensional structure, the nature of which remains uncertain. Several models of the amylopectin structure have been suggested through the years, and in this review two models are described, namely the "cluster model" and the "building block backbone model". The structure of the starch granules is discussed in light of both models.

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“…Although starch contains no amylose, similar to the waxy ae double mutant of rice, the waxy ae mutant o f maize displays an apparent AC of 34.5% (Jane et al, 1999). On the other hand, detailed structural analyses have demonstrated that those long chains do not originate from the real amylopectin of high-amylose starches, but from intermediate components (IC), which is a fraction consisting of branched molecules with molecular weights smaller than amylopectin but similar to amylose (Wang et al, 1993; Kasemsuwan et al, 1995) and is capable of escaping 1-butanol precipitation with amylopectin (Jane and Chen, 1992; Li et al, 2008; Peymanpour et al, 2016). When removing amylose from high-amylose starches, a mixture containing both IC and amylopectin is further separated using gel permeation chromatography (GPC) (Li et al, 2008).…”

Section: Factors Affecting Amylose Increase In High-amylose Cereal Cropsmentioning

confidence: 99%

“…When removing amylose from high-amylose starches, a mixture containing both IC and amylopectin is further separated using gel permeation chromatography (GPC) (Li et al, 2008). Peymanpour et al (2016) divided this mixture according to their distribution of molecular structure into high molecular weight fraction (HMF) and low molecular weight fraction (LMF). HMF is the typical amylopectin, whereas LMF corresponds to the IC fraction, which increases with AC and appears to have substantially more of long chains than HMF.…”

Section: Factors Affecting Amylose Increase In High-amylose Cereal Cropsmentioning

confidence: 99%

Progress in High-Amylose Cereal Crops through Inactivation of Starch Branching Enzymes

Wang

Chen

et al. 2017

Front. Plant Sci.

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High-amylose cereal starches provide many health benefits for humans. The inhibition or mutation of starch branching enzyme (SBE) genes is an effective method to develop high-amylose cereal crops. This review summarizes the development of high-amylose cereal crops through the inactivation of one or more SBE isoforms or combination with other genes. This review also reveals the causes of increase in amylose content in high-amylose crops. A series of changes, including amylopectin structure, crystalline structure, thermal properties, and hydrolysis properties, occurs as amylose content increases. The different morphological starch granules nominated as heterogeneous starch granules or differently stained starch granules are detected in high-amylose cereal crops. Detailed studies on four heterogeneous starch granules in high-amylose rice, which is developed by antisense RNA inhibition of SBEI/IIb, indicate that granules with different morphologies possess various molecular structures and physicochemical and functional properties. This variation diversifies their applications in food and non-food industries. However, current knowledge regarding how these heterogeneous starch granules form and why they exhibit regional distribution in endosperm remain largely unknown.

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On the molecular structure of the amylopectin fraction isolated from “high-amylose” ae maize starches

Cited by 20 publications

References 71 publications

Contributions of Three Starch Branching Enzyme Isozymes to the Fine Structure of Amylopectin in Rice Endosperm

Contributions of Three Starch Branching Enzyme Isozymes to the Fine Structure of Amylopectin in Rice Endosperm

Understanding Starch Structure: Recent Progress

Progress in High-Amylose Cereal Crops through Inactivation of Starch Branching Enzymes

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