scholarly journals Distinct Functions of STARCH SYNTHASE 4 Domains in Starch Granule Formation

2017 ◽  
Vol 176 (1) ◽  
pp. 566-581 ◽  
Author(s):  
Kuan-Jen Lu ◽  
Barbara Pfister ◽  
Camilla Jenny ◽  
Simona Eicke ◽  
Samuel C. Zeeman
Keyword(s):  
Starch Granule ◽  
Starch Synthase ◽  
Granule Formation

scholarly journals Starch synthase 4 is essential for coordination of starch granule formation with chloroplast division during Arabidopsis leaf expansion

2013 ◽  
Vol 200 (4) ◽  
pp. 1064-1075 ◽  
Author(s):  
Matilda Crumpton‐Taylor ◽  
Marilyn Pike ◽  
Kuan‐Jen Lu ◽  
Christopher M. Hylton ◽  
Regina Feil ◽  
...  
Keyword(s):  
Starch Granule ◽  
Chloroplast Division ◽  
Leaf Expansion ◽  
Starch Synthase ◽  
Granule Formation

The phenotype of soluble starch synthase IV defective mutants of Arabidopsis thaliana suggests a novel function of elongation enzymes in the control of starch granule formation

2007 ◽  
Vol 49 (3) ◽  
pp. 492-504 ◽  
Author(s):  
Isaac Roldán ◽  
Fabrice Wattebled ◽  
M. Mercedes Lucas ◽  
David Delvallé ◽  
Veronique Planchot ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Starch Granule ◽  
Soluble Starch ◽  
Starch Synthase ◽  
Granule Formation

scholarly journals STARCH SYNTHASE 4 is required for normal starch granule initiation in amyloplasts of wheat endosperm

2021 ◽  
Author(s):  
Erica Hawkins ◽  
Jiawen Chen ◽  
Alexander Watson-Lazowski ◽  
Jennifer Ahn-Jarvis ◽  
J. Elaine Barclay ◽  
...  
Keyword(s):  
Starch Granule ◽  
Starch Content ◽  
Tetraploid Wheat ◽  
Pollen Grains ◽  
Starch Synthase ◽  
Spatiotemporal Pattern ◽  
List Type ◽  
Grain Development ◽  
Granule Formation ◽  
Endosperm Starch

SUMMARYStarch granule initiation is poorly understood at the molecular level. The glucosyltransferase, STARCH SYNTHASE 4 (SS4), plays a central role in granule initiation in Arabidopsis leaves, but its function in cereal endosperms is unknown. We investigated the role of SS4 in wheat, which has a distinct spatiotemporal pattern of granule initiation during grain development.We generated TILLING mutants in tetraploid wheat (Triticum turgidum) that are defective in both SS4 homoeologs. The morphology of endosperm starch was examined in developing and mature grains.SS4 deficiency led to severe alterations in endosperm starch granule morphology. During early grain development, while the wild type initiated single ‘A-type’ granules per amyloplast, most amyloplasts in the mutant formed compound granules due to multiple initiations. This phenotype was similar to mutants deficient in B-GRANULE CONTENT 1 (BGC1). SS4 deficiency also reduced starch content in leaves and pollen grains.We propose that SS4 and BGC1 are required for the proper control of granule initiation during early grain development that leads to a single A-type granule per amyloplast. The absence of either protein results in a variable number of initiations per amyloplast and compound granule formation.

scholarly journals Toward an understanding of the biogenesis of the starch granule. Determination of granule-bound and soluble starch synthase functions in amylopectin synthesis.

1994 ◽  
Vol 269 (40) ◽  
pp. 25150-25157
Author(s):  
M.L. Maddelein ◽  
N. Libessart ◽  
F. Bellanger ◽  
B. Delrue ◽  
C. D'Hulst ◽  
...  
Keyword(s):  
Starch Granule ◽  
Soluble Starch ◽  
Starch Synthase

Physiology of Cereal Grain II. Starch Granule Formation in the Developing Barley Kernel

1959 ◽  
Vol 12 (2) ◽  
pp. 146 ◽  
Author(s):  
LH May ◽  
MS Buttrose
Keyword(s):  
Starch Granule ◽  
Dry Weight ◽  
Type A ◽  
Starch Granules ◽  
Type B ◽  
Granule Formation ◽  
Rate Of Increase ◽  
Cereal Grain ◽  
Barley Kernel ◽  
B Granules

Types, numbers, volumes, and weights of starch granules in the barley endosperm were measured at different times from anthesis to maturity. The formation of two types of granule was confirmed: the first (type A) was initiated until 15 days after anthesis; the second (type B) between 18 and 30 days. At maturity there were approximately 10 times as many type B granules as type A, although the latter made up 90 per cent. of the total granule volume. There was a linear relationship between starch granule and endosperm volume throughout kernel development, while the rate of increase in volume per unit granule volume was the same, irrespective of granule size, at anyone time. Starch weight increased as endosperm dry weight increased although the precise form of this relationship is in doubt. The interrelationships between starch granule weight and volume, and also endosperm dry weight and volume, suggest that both starch granules and endosperm increase in density during development.

scholarly journals Interplay Between the N-Terminal Domains of Arabidopsis Starch Synthase 3 Determines the Interaction of the Enzyme With the Starch Granule

2021 ◽  
Vol 12 ◽  
Author(s):  
Francisco M. Gámez-Arjona ◽  
Ángel Mérida
Keyword(s):  
Starch Granule ◽  
Coiled Coil ◽  
Terminal Region ◽  
Starch Synthase ◽  
Full Length ◽  
Localization Pattern ◽  
Binding Domains ◽  
Starch Synthases ◽  
Linear Chains

The elongation of the linear chains of starch is undertaken by starch synthases. class 3 of starch synthase (SS3) has a specific feature: a long N-terminal region containing starch binding domains (SBDs). In this work, we analyze in vivo the contribution of these domains to the localization pattern of the enzyme. For this purpose, we divided the N-terminal region of Arabidopsis SS3 in three domains: D1, D2, and D3 (each of which contains an SBD and a coiled-coil site). Our analyses indicate that the N-terminal region is sufficient to determine the same localization pattern observed with the full-length protein. D2 binds tightly the polypeptide to the polymer and it is necessary the contribution of D1 and D3 to avoid the polypeptide to be trapped in the growing polymer. The localization pattern of Arabidopsis SS3 appears to be the result of the counterbalanced action of the different domains present in its N-terminal region.

scholarly journals Structure & acceptor recognition of CLG1_GBSS, a cyanobacterial starch synthase.

2014 ◽  
Vol 70 (a1) ◽  
pp. C1167-C1167
Author(s):  
Jose Cuesta-Seijo ◽  
Morten Nielsen ◽  
Monica Palcic
Keyword(s):  
Starch Granule ◽  
Glycogen Synthase ◽  
Starch Synthesis ◽  
Caloric Intake ◽  
Starch Synthase ◽  
Complex Structures ◽  
Asymmetric Unit ◽  
Group V ◽  
The World ◽  
Shed Light

Starch synthesis was thought to occur exclusively in archaeplastida, which include green algae and land plants. Recently, amylopectin-like polymers have been identified in group V cyanobacteria[1]. In particular, a newly isolated cyanobacterium, CLG1, synthetizes granules containing both amylose and amylopectin essentially identical to plant starch[2]. These cyanobacteria are believed to have contributed some of the key starch synthesizing enzymes to plants. Starch synthases are the enzymes responsible for elongation of the maltooligosaccharide chains that compose the starch granule, working in concert with many other enzymes to create the complex structures of amylopectin and amylose. Here we report the crystal structure, refined to 2.2 Å, of GBSS, the granule bound starch synthase responsible for amylose synthesis in CLG1, in complex with ADP and either acarbose or glucose in the acceptor binding site. The structure reveals different conformational states of the ternary complex in three copies of GBSS in the asymmetric unit. The variations between monomers shed light on changes on the protein upon substrate recognition. In particular it clarifies the effect of acceptor binding in the conformation of the active site. This structure also illustrates the conformation of parts of the primary sequence that were absent from all plant starch synthase structures to date. Features in this structure are compared to both glycogen synthase and starch synthase structures. Both the similarities and the differences advance our knowledge on the necessary components of a starch synthase and point the way to their targeted structural and functional modification. The world-wide demand of cereals is expected to double from its current values by 2050 (FAO). Modification of proteins involved in starch synthesis, be it via traditional breeding or via genetic engineering, will likely be crucial to meeting the caloric intake needs of the human population in the coming decades.

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