Functional Interactions between Heterologously Expressed Starch-Branching Enzymes of Maize and the Glycogen Synthases of Brewer’s Yeast Seo, Beom-Seok Kim, Seungtaek Scott, Marvin Singletary, George Scott, Marvin Wong, Kit-sum James, Martha Myers, Alan
dc.contributor.department Food Science and Human Nutrition
dc.contributor.department Biochemistry, Biophysics and Molecular Biology
dc.contributor.department Agronomy 2018-02-17T13:44:03.000 2020-06-29T23:07:06Z 2020-06-29T23:07:06Z 2002-04-01
dc.description.abstract <p>Starch-branching enzymes (SBEs) catalyze the formation of α(1→6) glycoside bonds in glucan polymers, thus, affecting the structure of amylopectin and starch granules. Two distinct classes of SBE are generally conserved in higher plants, although the specific role(s) of each isoform in determination of starch structure is not clearly understood. This study used a heterologous in vivo system to isolate the function of each of the three known SBE isoforms of maize (<em>Zea mays</em>) away from the other plant enzymes involved in starch biosynthesis. The ascomycete Brewer's yeast (<em>Saccharomyces cerevisiae</em>) was employed as the host species. All possible combinations of maize SBEs were expressed in the absence of the endogenous glucan-branching enzyme. Each maize SBE was functional in yeast cells, although SBEI had a significant effect only if SBEIIa and SBEIIb also were present. SBEI by itself did not support glucan accumulation, whereas SBEIIa and SBEIIb both functioned along with the native glycogen synthases (GSs) to produce significant quantities of α-glucan polymers. SBEIIa was phenotypically dominant to SBEIIb in terms of glucan structure. The specific branching enzyme present had a significant effect on the molecular weight of the product. From these data we suggest that SBEs and GSs work in a cyclically interdependent fashion, such that SBE action is needed for optimal GS activity; and GS, in turn, influences the further effects of SBE. Also, SBEIIa and SBEIIb appear to act before SBEI during polymer assembly in this heterologous system.</p>
dc.description.comments <p>This article is from <em>Plant Physiology</em> 128 (2002): 1189, doi: <a href="" target="_blank">10.1104/pp.010756</a>.</p>
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dc.identifier archive/
dc.identifier.articleid 1081
dc.identifier.contextkey 8190331
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath agron_pubs/85
dc.language.iso en
dc.source.bitstream archive/|||Sat Jan 15 02:12:27 UTC 2022
dc.source.uri 10.1104/pp.010756
dc.subject.disciplines Agronomy and Crop Sciences
dc.subject.disciplines Biochemistry
dc.subject.disciplines Biophysics
dc.subject.disciplines Food Science
dc.subject.disciplines Human and Clinical Nutrition
dc.subject.disciplines Molecular Biology
dc.title Functional Interactions between Heterologously Expressed Starch-Branching Enzymes of Maize and the Glycogen Synthases of Brewer’s Yeast
dc.type article
dc.type.genre article
dspace.entity.type Publication
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