The double-helical nature of the crystalline part of A-starch.
TL;DR: A new three-dimensional structure of the crystalline part of A-starch is described in which the unit cell contains 12 glucose residues located in two left-handed, parallel-stranded double helices packed in a parallel fashion; four water molecules are located between these helices.
About: This article is published in Journal of Molecular Biology.The article was published on 1988-05-20. It has received 561 citations till now. The article focuses on the topics: Helix & Pyranose.
Citations
More filters
TL;DR: This review will focus first on the present understanding of the structures of amylose and amylopectin and their organization within the granule, and then on the biosynthetic mechanisms explaining the biogenesis of starch in plants.
1,839 citations
TL;DR: In this paper, a review of the current state of knowledge about starch structure in perspective and integrating aspects of starch composition, interactions, architecture and functionality is presented, and the authors highlight the need to understand in more depth the structure of starch granules and how this complex organisation controls functionality.
1,436 citations
Cites background from "The double-helical nature of the cr..."
...…righthanded, parallel helices, subsequent work showed they may be left-handed (Oostergetel and van Bruggen, 1993), anti-parallel and left-handed (Eisenhaber and Schultz, 1992), but most probably, parallel and left-handed (Imberty et al., 1987, 1988a,b, 1991; Imberty and Pérez, 1988; Gidley, 1989)....
[...]
...…and Bouchet, 1986; Galliard and Bowler, 1987; Gérard et al., 2000; Gernat et al., 1990; Gidley, 1987; Hedley et al., 2002; Imberty and Perez, 1988; Imberty et al., 1987, 1988a,b, 1991; Jenkins et al., 1993; McPherson and Jane, 1999; Sarko and Wu, 1978; Seib, 1994; Tester and Karkalas, 2002;…...
[...]
TL;DR: The major carbohydrate of tuber and root crops is starch, which accounts for 16-24% of their total weight as mentioned in this paper, and substantial progress has been made in understanding the relationship between starch structure and physicochemical properties.
1,215 citations
TL;DR: In this paper, the disruption of molecular oders which occur during the gelatinisation of starch granules has been studied by isolating dried samples from maize, waxy maize, wheat, potatoe, and tapioca starches after defined thermal pre-treatments.
1,090 citations
TL;DR: The structure of the starch granule slowly unravels with new insight into key structural features as discussed by the authors, and the most recent findings for the structure of amylose and amylopectin are reported.
Abstract: Recent developments in methods and instrumentation have contributed to major advances in our understanding of the fine structure of amylose and amylopectin. The structure of the starch granule slowly unravels with new insight into key structural features. Following a brief presentation of the structural features common to all starches, the most recent findings for the structure of amylose and amylopectin are reported. The organization of different types of chains in amylopectin is discussed with a critical review of the 'cluster' model leading to the presentation of alternative models. The locations of molecular components in the starch granule are described according to a progress structural order. The description of the crystalline components is followed by a presentation of their supramolecular arrangements. The crystalline components comprise platelet nanocrystals which have already been identified and characterized, and other less well characterized 'blocklet components'. The location and state of amylose within the granule is also presented. This comprehensive review aims at distinguishing between those structural features that have received widespread acceptance and those that are still under debate, with the ambition of being educational and to provide stimulation for further fundamental investigation into the starch granule as a macromolecular assembly.
1,086 citations
Cites background or result from "The double-helical nature of the cr..."
...[81] Pfannemuller, B., Influence of chain length of short monodisperse amylose on the formation of A-type and B-type Xray diffraction patterns....
[...]
...The study was performed on two allomorphs, double maize mutants of A- and B-type (wxdu and aewx, respectively)....
[...]
...They display A- and B-type X-ray diffraction pattern [59, 86, 87]....
[...]
...These specimens contain 60% of A-type structure and 40% of B-type structure; and these two crystalline phases co-exist within the same granule....
[...]
...[116] Genkina, N. K., Wikman, J., Bertoft, E., Yurye, V.P., Effects of structural imperfection on gelatinization characteristics of amylopectin starches with A- and B-type crystallinity....
[...]
References
More filters
TL;DR: The distribution of chain lengths in the amylopectins of starches from 20 species (11 A-, 6 B-, and 3 C-type) were characterised by h.p.l.c. as mentioned in this paper.
524 citations
TL;DR: The crystal structure of A-amylose is based on parallel-stranded, right-handed double helices as mentioned in this paper, which results in nearly hexagonal close-packing, and the similarities in packing suggest that interconversions of A and B are possible.
399 citations
TL;DR: In this article, the authors used cross polarization/magic angle spinning (CP/MAS) 13C NMR spectra for starches from various botanical origins and analyzed by comparison with model materials.
Abstract: Cross polarization/magic angle spinning (CP/MAS) 13C NMR spectra have been obtained for starches from various botanical origins and analyzed by comparison with model materials. All features of starch 13C CP/MAS spectra are accounted for by a combination of amorphous (single chain) and ordered (double helix) components. The proportion of each of these structural types present in native starches can be estimated from 13C CP/MAS spectra. This provides the first approach to the quantitative analysis of starch molecular structures; the values obtained can be compared with estimates of longer range ordering from X-ray powder diffraction. C-1 and C-4 carbons (i.e., those sites involved in glycosidic linkage) show large chemical shift displacements between amorphous and crystalline materials indicating substantial conformational differences. Chemical shift displacements between the two common crystalline types (A and B) of starches are much smaller but model crystalline materials show polymorphic variations in C-1 multiplicity which can be ascribed to known differences in the symmetry of double helix packing. The chemical shift ranges observed for spectral features of amorphous materials suggest that part of the amorphous component of starches has a well-defined conformation.
339 citations
TL;DR: It was found that U0 was essentially constant within each class, thus allowing these average values to be used to calculate ΔU for all molecules in each class and satisfying agreement between the calculated values and experimental values of ΔU was found.
Abstract: A method is proposed for calculating internal rotation barriers in ethanelike molecules based on two effects, exchange interactions of the electrons in bonds adjacent to the bond about which internal rotation occurs and nonbonded or van der Waals interactions. A modified Buckingham or ``6‐exp'' potential is used for the nonbonded interactions and a semiempirical method is used to obtain the constants in the 6‐exp potential for the various kinds of nonbonded interactions. The equation for U(ω) contains one adjustable parameter, U0, which theoretically should be constant for all molecules within certain classes. An average value for U0 is obtained for each class from selected microwave values of ΔU by letting ΔU have the microwave experimental value and solving for U0. It was found that U0 was essentially constant within each class, thus allowing these average values to be used to calculate ΔU for all molecules in each class. Satisfactory agreement between the calculated values and experimental values of ΔU...
297 citations
228 citations