Structure of Amylopectins from <i>ae</i>‐Containing Maize Starches

Klucinec, Jeffrey D.; Thompson, Donald B.

doi:10.1094/cchem.2002.79.1.19

Cited by 68 publications

(78 citation statements)

References 26 publications

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“…Comparison among the four genotypes revealed that the profile for sbe1a wx is essentially the same as for wx. Consistent with previous studies, the starch of ae wx comprises considerably more long chains and fewer short chains than wx and sbe1a wx (Yuan et al, 1993;Klucinec and Thompson, 2002;Yao et al, 2002). The CL profile of sbe1a ae wx differs from that of ae wx exhibiting fewer long chains and more short chains.…”

Section: Amylopectin Fine Structuresupporting

confidence: 86%

“…For calculating these parameters, the y axes of CL profiles of b-limit dextrin were transformed into molar amount as described by Klucinec and Thompson (2002). Based on the minima or inflections observed, the profiles were divided into regions of A chains, intracluster B chains (B1), and intercluster B chains (Hizukuri, 1986).…”

Section: Branch Density Of Amylopectinmentioning

confidence: 99%

“…While the in vitro properties of SBEIa differ from those of SBEIIa and SBEIIb (Guan and Preiss, 1993;Takeda et al, 1993), the sbe1a or sbe2a single mutants obtained using Mu-mediated transposon mutagenesis indicated that the chain-length (CL) profiles of starch produced in endosperm in vivo were not affected by the deficiency of either SBEIa or SBEIIa (Blauth et al, 2001(Blauth et al, , 2002. Conversely, the ae mutant, which is deficient in SBEIIb, results in major changes in endosperm amylopectin structure (Yuan et al, 1993;Shi and Seib, 1995;Klucinec and Thompson, 2002). The in vivo functional behavior of these three single Sbe mutants led us to hypothesize that during amylopectin biosynthesis in maize endosperm, the function of SBEIIb is predominant to that of both SBEIa and SBEIIa, and therefore the sbe1a mutant might affect starch structure only in an ae background.…”

mentioning

confidence: 99%

“…This latter relationship may well be the outcome of in vivo SBE activity (Thompson, 2000) and was used to characterize the functional behavior of SBE isoforms. While amylopectin CL profiles provide a general description of all the constituent chains present, further analysis of the CL profile of amylopectin b-limit dextrin is necessary to understand the branching pattern of the clusters Inouchi et al, 1987;Yuan et al, 1993;Yun and Matheson, 1993;Klucinec and Thompson, 2002). Using high-performance sizeexclusion chromatography (HPSEC), Klucinec and Thompson (2002) identified a shorter chain population from intracluster B chains in several genotypes.…”

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confidence: 99%

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Maize Starch-Branching Enzyme Isoforms and Amylopectin Structure. In the Absence of Starch-Branching Enzyme IIb, the Further Absence of Starch-Branching Enzyme Ia Leads to Increased Branching

2004

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Previous studies indicated that the deficiency of starch-branching enzyme (SBE) Ia in the single mutant sbe1a::Mu (sbe1a) has no impact on endosperm starch structure, whereas the deficiency of SBEIIb in the ae mutant is well known to reduce the branching of starch. We hypothesized that in maize (Zea mays) endosperm, the function of SBEIIb is predominant to that of SBEIa, and SBEIa would have an observable effect only on amylopectin structure in the absence of SBEIIb. To test this hypothesis, the mutant sbe1a was introgressed into lines containing either wx (lacking the granule-bound starch synthase GBSSI) or ae wx (lacking both SBEIIb and GBSSI) in the W64A background. Both western blotting and zymogram analysis confirmed the SBEIa deficiency in sbe1a wx and sbe1a ae wx, and the SBEIIb deficiency in ae wx and sbe1a ae wx. Using zymogram analysis, no pleiotropic effects of sbe1a genes on SBEIIa, starch synthase, or starch-debranching enzyme isoforms were observed. Highperformance size exclusion chromatography analysis shows that the chain-length profiles of amylopectin as well as b-limit dextrin were indistinguishable between wx and sbe1a wx, whereas significant differences for both were observed between ae wx and sbe1a ae wx, suggesting an effect of SBEIa on amylopectin biosynthesis that is observable only in the absence of SBEIIb. The amylopectin branch density and the average number of branches per cluster were both higher in endosperm starch from sbe1a ae wx than from ae wx. These results indicate possible functional interactions between SBE isoforms that may involve enzymatic inhibition. Both the cluster repeat distance and the distance between branch points on the short intracluster chains were similar for all genotypes however, suggesting a similar pattern of individual SBE isoforms in cluster initiation and the determination of branch point location.Starch biosynthesis involves the activities of four enzymes: ADP-Glc pyrophosphorylase, starch synthase (SS), starch-branching enzyme (SBE), and starch-debranching enzyme (DBE;Smith et al., 1997). The coordinated functions of these enzymes result in two forms of starch molecules: amylose, an essentially linear glucan chain consisting of a-1,4 linkages, and amylopectin, a highly branched glucan chain with multiple branch points formed by a-1,6 linkages.SBE catalyzes the formation of branch points within glucan chains by cleaving an a-1,4 linkage and reattaching the chain to a glucan chain via a-1,6 bond. Three isoforms of SBE (SBEIa, SBEIIa, and SBEIIb) have been identified in maize (Zea mays; Boyer and Preiss, 1978;Dang and Boyer, 1988), and their expression patterns differ considerably (Gao et al., 1996). While the in vitro properties of SBEIa differ from those of SBEIIa and SBEIIb (Guan and Preiss, 1993;Takeda et al., 1993), the sbe1a or sbe2a single mutants obtained using Mu-mediated transposon mutagenesis indicated that the chain-length (CL) profiles of starch produced in endosperm in vivo were not affected by the deficiency of either SBEIa or SBEIIa (Blau...

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Section: Amylopectin Fine Structuresupporting

confidence: 86%

Section: Branch Density Of Amylopectinmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Maize Starch-Branching Enzyme Isoforms and Amylopectin Structure. In the Absence of Starch-Branching Enzyme IIb, the Further Absence of Starch-Branching Enzyme Ia Leads to Increased Branching

2004

Self Cite

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“…SBEIIa might thus play a role in leaf starch biosynthesis and be involved in the initiation of starch biosynthesis. SBEIIb mutant was originally found to have a high amylose content [83], which was later shown in maize and rice to be because the higher amount of amylose is actually from the A (internal) amylopectin chains [80,84,85]. Moreover, a rice SBEIIb mutant had a 50% reduction of SSI activity, suggesting that SBEIIb and SSI may interact in vivo [80].…”

Section: Starch-branching Enzymes (Sbes)mentioning

confidence: 99%

Recent progress toward understanding the role of starch biosynthetic enzymes in the cereal endosperm

Li¹,

Powell²,

Gilbert

2017

Amylase

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Abstract:Starch from cereal endosperm is a major energy source for many mammals. The synthesis of this starch involves a number of different enzymes whose mode of action is still not completely understood. ADPglucose pyrophosphorylase is involved in the synthesis of starch monomer (ADP-glucose), a process, which almost exclusively takes place in the cytosol. ADPglucose is then transported into the amyloplast and incorporated into starch granules by starch synthase, starch-branching enzyme and debranching enzyme. Additional enzymes, including starch phosphorylase and disproportionating enzyme, may be also involved in the formation of starch granules, although their exact functions are still obscure. Interactions between these enzymes in the form of functional complexes have been proposed and investigated, resulting more complicated starch biosynthetic pathways. An overall picture and recent advances in understanding of the functions of these enzymes is summarized in this review to provide insights into how starch granules are synthesized in cereal endosperm.

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Hydrothermal treatment and iodine binding provide insights into the organization of glucan chains within the semi‐crystalline lamellae of corn starch granules

Vamadevan¹,

Hoover

Bertoft³

et al. 2014

Biopolymers

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The importance of glucan chains that pass through both the amorphous and crystalline lamellae (tie chains) in the organization of corn starch granules was studied using heat-moisture treatment (HMT), annealing (ANN), and iodine binding. Molecular structural analysis showed that hylon starches (HV, HVII, and HVIII) contained higher proportion of intermediate glucan chains (HVIII > HVII > HV) than normal corn (CN) starch. Wide angle X-ray scattering revealed that on HMT, the extent of polymorphic transition in hylon starches decreased with increasing proportion of intermediate and long chains. Iodine treated hylon starches exhibited increased order in the V-type polymorphism as evidenced by the intense peak at 20° 2θ and the strong reflection intensity at 7.5° 2θ and the extent of the change depended on the type of hylon starch. DSC results showed that the gelatinization enthalpy of CN and waxy corn starch (CW) remained unchanged after ANN. However, hylon starches showed a significant increase in enthalpy with more distinct endotherms after ANN. It can be concluded that tie chains influence the organization of crystalline lamellae in amylose extender mutant starches.

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Structure of Amylopectins from ae‐Containing Maize Starches

Cited by 68 publications

References 26 publications

Maize Starch-Branching Enzyme Isoforms and Amylopectin Structure. In the Absence of Starch-Branching Enzyme IIb, the Further Absence of Starch-Branching Enzyme Ia Leads to Increased Branching

Maize Starch-Branching Enzyme Isoforms and Amylopectin Structure. In the Absence of Starch-Branching Enzyme IIb, the Further Absence of Starch-Branching Enzyme Ia Leads to Increased Branching

Recent progress toward understanding the role of starch biosynthetic enzymes in the cereal endosperm

Hydrothermal treatment and iodine binding provide insights into the organization of glucan chains within the semi‐crystalline lamellae of corn starch granules

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