Single molecule optical diffraction: A tool for understanding the structure of triple stranded left-hand helical cellulose

1989 ◽  
Vol 47 ◽  
pp. 1024-1025
Author(s):  
George C. Ruben ◽  
William Krakow
Keyword(s):  
Single Molecule ◽  
Helical Structure ◽  
Optical Diffraction ◽  
Maximum Diameter ◽  
Primary Cell Wall ◽  
Cellulose Synthesis ◽  
Left Hand ◽  
Left Handed ◽  
Freeze Dried ◽  
Diffraction Patterns

Tobacco primary cell wall and normal bacterial Acetobacter xylinum cellulose formation produced a 36.8±3Å triple-stranded left-hand helical microfibril in freeze-dried Pt-C replicas and in negatively stained preparations for TEM. As three submicrofibril strands exit the wall of Axylinum , they twist together to form a left-hand helical microfibril. This process is driven by the left-hand helical structure of the submicrofibril and by cellulose synthesis. That is, as the submicrofibril is elongating at the wall, it is also being left-hand twisted and twisted together with two other submicrofibrils. The submicrofibril appears to have the dimensions of a nine (l-4)-ß-D-glucan parallel chain crystalline unit whose long, 23Å, and short, 19Å, diagonals form major and minor left-handed axial surface ridges every 36Å.The computer generated optical diffraction of this model and its corresponding image have been compared. The submicrofibril model was used to construct a microfibril model. This model and corresponding microfibril images have also been optically diffracted and comparedIn this paper we compare two less complex microfibril models. The first model (Fig. 1a) is constructed with cylindrical submicrofibrils. The second model (Fig. 2a) is also constructed with three submicrofibrils but with a single 23 Å diagonal, projecting from a rounded cross section and left-hand helically twisted, with a 36Å repeat, similar to the original model (45°±10° crossover angle). The submicrofibrils cross the microfibril axis at roughly a 45°±10° angle, the same crossover angle observed in microflbril TEM images. These models were constructed so that the maximum diameter of the submicrofibrils was 23Å and the overall microfibril diameters were similar to Pt-C coated image diameters of ∼50Å and not the actual diameter of 36.5Å. The methods for computing optical diffraction patterns have been published before.

scholarly journals Single bacteriorhodopsin molecules revealed on both surfaces of freeze-dried and heavy metal-decorated purple membranes.

1981 ◽  
Vol 90 (1) ◽  
pp. 153-159 ◽  
Author(s):  
D Studer ◽  
H Moor ◽  
H Gross
Keyword(s):  
Image Processing ◽  
Hexagonal Lattice ◽  
Purple Membrane ◽  
Optical Diffraction ◽  
Freeze Dried ◽  
Structural Details ◽  
Triplet Structure ◽  
Diffraction Patterns ◽  
Image Details ◽  
Purple Membranes

The flat sheets of the purple membrane from Halobacterium halobium contain only a single protein (bacteriorhodopsin) arranged in a hexagonal lattice. After freeze-drying at -80 degrees C (a method that is superior to air-drying), shadowing with tantalum/tungsten, and image processing, structural details on both surfaces are portrayed in the range of 2 nm. One surface is rough and lattice lines are clearly visible, whereas the other is smooth and the hexagonal order seems to be absent. The optical diffraction patterns, however, indicate a hexagonal lattice for both surfaces. In addition, these diffraction patterns are characteristic and easily distinguished. The orientation of the two surfaces was identified by silver decoration: partial condensation of silver on purple membranes enabled the smooth surface to be identified as the plasmatic and the rough surface as the exoplasmic surface. After image processing, the exoplasmic surface shows a triplet structure which exactly fits the projected structure determined by Unwin and Henderson (1975. Nature(Lond.). 257:28-32) at molecular resolution, whereas, on the plasmatic surface, four image details per unit cell are visible. Three of them match the arrangement of bacteriorhodopsin, whereas the fourth must be located over a lipidic array. Summarizing these results, it is possible to show the part of each single bacteriorhodopsin protein that is present in the surfaces of the purple membrane. By "shadowing" the membranes perpendicularly, we prove that these components of the surfaces are mainly portrayed by a decoration effect of the tantalum/tungsten condensate.

scholarly journals Arrangement of subunits in microtubules with 14 profilaments.

1980 ◽  
Vol 87 (2) ◽  
pp. 521-526 ◽  
Author(s):  
G M Langford
Keyword(s):  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Beta Subunit ◽  
Simultaneous Imaging ◽  
Left Handed ◽  
Resolution Electron ◽  
Dogfish Shark ◽  
Diffraction Patterns ◽  
Two Sides ◽  
Brain Tubulin

The structure of 14-protofilament microtubules reassembled from dogfish shark brain tubulin was analyzed by high resolution electron microscopy and optical diffraction. The simultaneous imaging of the protofilaments from near and far sides of these tubules produces a moiré pattern with a period of approximately 96 nm. Optical diffraction patterns show that the 5-nm spots that arise from the protofilaments for the two sides of the tubule are not coincident but lie off the equator by a distance of 1/192 nm-1. These data provide evidence that in reassembled microtubules containing 14 protofilaments, the protofilaments are tilted 1.5 degrees with respect to the long axis of the tubule, giving a left-handed superhelix with a pitch of 2.7 micron. The hypothesis is that the tilt of the protofilaments occurs to accommodate the 14th protofilament. It is determined that when the 14th protofilament is incorporated, the 3-start helix is maintained, but the pitch angle changes from 10.5 degrees to 11.2 degrees, the angle between protofilaments measured from the center of the microtubule changes by 2 degrees, and the dimer lattice is discontinuous. These observations show that the tubulin molecule is sufficiently flexible to accomodate slight distortions at the lateral bonding sites and that the lateral bonding regions of the alpha and beta monomers are sufficiently similar to allow either alpha-alpha and beta-beta subunit pairing or alpha-beta subunit pairing.

Chain arrangement and sense of the α-helix in poly-L-alanine fibres

1959 ◽  
Vol 249 (1256) ◽  
pp. 30-41 ◽  
Keyword(s):  
Optical Diffraction ◽  
Peptide Sequence ◽  
X Ray Diffraction ◽  
Repeat Distance ◽  
Left Handed ◽  
Diffraction Patterns ◽  
Α Helix ◽  
Limited Sequence ◽  
Good Agreement ◽  
Complete Account

The X-ray diffraction pattern of poly-L-alanine fibres has been compared with optical diffraction patterns of a-helices. With bond lengths and angles not significantly different from those found in simple compounds, good agreement is found with right-handed (but not with left-handed) helices. It is necessary to suppose that the direction of the peptide sequence of chains in the crystallites is random. Helices with a long repeat distance are found to pack in a way which produces a limited sequence of residues, spaced at 4.5 A, in which displacements from steric effects can be expected. It is shown how this may produce a meridian reflexion at 4.4 A, as observed. A complete account of all features of the packing is not given, however, and hardly seems to be practicable.

Application of optical diffraction to helical structures in the bacteriophage tail

1971 ◽  
Vol 261 (837) ◽  
pp. 181-195 ◽  
Keyword(s):  
Visual Inspection ◽  
Structural Parameters ◽  
Helical Structure ◽  
Structural Data ◽  
Optical Diffraction ◽  
Structural Parameter ◽  
Helical Structures ◽  
The Core ◽  
Diffraction Patterns

First, a brief account is given of the principles underlying the use of the optical diffraction pattern of a perfectly helical particle to determine its helical lattice. The practical value and difficulties of this method are then revealed by a survey of its application to three different helical components of the T-even bacteriophage tail. The analysis of the structure of contracted sheath is much facilitated by the existence of two kinds of particle (contracted sheath and polysheath) with apparently the same helical lattice. Polysheath yields excellent optical diffraction patterns, and contracted sheath (which does not) reveals directly the number of helices in one set (information unobtainable from polysheath). The clear annuli of the extended sheath simplify the determination of all its structural parameters except for the number of helices in any set. For estimating this number, visual inspection is in one respect superior to optical diffraction, but an unambiguous solution has not hitherto been possible. The helical structure of the core is so faint that optical diffraction is indispensable for obtaining reliable structural data. Even with this method, only one structural parameter has been determined so far: the core is composed of annuli whose spacing is apparently identical with that of the annuli of the extended sheath.

Light Optical Diffraction Studies of Macromolecular Ultrastructure

1970 ◽  
Vol 28 ◽  
pp. 258-259
Author(s):  
Glen B. Haydon
Keyword(s):  
High Resolution ◽  
Diffraction Analysis ◽  
Diffraction Pattern ◽  
Electron Micrographs ◽  
Optical Diffraction ◽  
Electron Micrograph ◽  
Its Analysis ◽  
Resolution Electron ◽  
Diffraction Patterns

Analysis of light optical diffraction patterns produced by electron micrographs can easily lead to much nonsense. Such diffraction patterns are referred to as optical transforms and are compared with transforms produced by a variety of mathematical manipulations. In the use of light optical diffraction patterns to study periodicities in macromolecular ultrastructures, a number of potential pitfalls have been rediscovered. The limitations apply to the formation of the electron micrograph as well as its analysis.(1) The high resolution electron micrograph is itself a complex diffraction pattern resulting from the specimen, its stain, and its supporting substrate. Cowley and Moodie (Proc. Phys. Soc. B, LXX 497, 1957) demonstrated changing image patterns with changes in focus. Similar defocus images have been subjected to further light optical diffraction analysis.

Crystalline order to a resolution of 4.7 A in the sheath of Methanospirilium hungatii: A cross-beta structure

1984 ◽  
Vol 42 ◽  
pp. 214-215
Author(s):  
Murray Stewart ◽  
T.J. Beveridge ◽  
D. Sprott
Keyword(s):  
Cell Wall ◽  
Single Layer ◽  
Uranyl Acetate ◽  
Optical Diffraction ◽  
Tube Axis ◽  
Basic Subunit ◽  
Beta Structure ◽  
Diffraction Patterns ◽  
Protein Treatment ◽  
General Appearance

The archaebacterium Methanospirillum hungatii has a sheath as part of its cell wall which is composed mainly of protein. Treatment with dithiothreitol or NaOH released the intact sheaths and electron micrographs of this material negatively stained with uranyl acetate showed flattened hollow tubes, about 0.5 μm diameter and several microns long, in which the patterns from the top and bottom were superimposed. Single layers, derived from broken tubes, were also seen and were more simply analysed. Figure 1 shows the general appearance of a single layer. There was a faint axial periodicity at 28.5 A, which was stronger at irregular multiples of 28.5 A (3 and 4 times were most common), and fine striations were also seen at about 3° to the tube axis. Low angle electron diffraction patterns (not shown) and optical diffraction patterns (Fig. 2) from these layers showed a complex meridian (as a result of the irregular nature of the repeat along the tube axis) which showed a clear maximum at 28.5 A, consistent with the basic subunit spacing.

Mixed Handedness and Achievement Test Scores of Middle School Boys

2008 ◽  
Vol 107 (2) ◽  
pp. 497-506
Author(s):  
P. S. B. Sarma
Keyword(s):  
Middle School ◽  
At Risk ◽  
Test Scores ◽  
Fourth Grade ◽  
Achievement Test ◽  
Normal Curve ◽  
Left Hand ◽  
Left Handed ◽  
Academic Deficits ◽  
The Right

The purpose of the study was to replicate findings of an earlier study of fourth grade boys manifesting mixed handedness with a sample. Among 32 mixed-handed boys in Grades 6 to 8, the right-handed writer, left-handed thrower group obtained low spelling scores (Normal Curve Equivalent Scores) on the California Achievement Test significantly more frequently than the left-handed writer, right-handed thrower group. These findings are consistent with data for Grade 4 boys in the earlier study. Findings strengthen the hypotheses that mixed handedness is not a unitary neuropsychological entity and that boys who write with the right hand and throw with the left hand might be at risk for certain academic deficits.

scholarly journals Arrangement of subunits in microribbons from Giardia

1981 ◽  
Vol 47 (1) ◽  
pp. 167-185 ◽  
Author(s):  
D.V. Holberton
Keyword(s):  
Inner Core ◽  
Giardia Duodenalis ◽  
Optical Diffraction ◽  
Third Order ◽  
The Third ◽  
Face Images ◽  
Face View ◽  
Diffraction Patterns ◽  
Vertical Spacing ◽  
Giardia Muris

Ultrasound has been used to disperse the cytoplasm of Giardia muris and Giardia duodenalis trophozoites, releasing disk cytoskeletons for negative staining and study by electron microscopy. Sonication also breaks down the corss-bridges uniting microribbons in disks. Individual ribbons and small bundles of these structures, are found in these preparations and have been imaged both from their edges and in flat face view. The outer layers of ribbons are 2 sheets of regularly arranged globular subunits, held apart by a fibrous inner core. The axial repeat of the microribbon is 15 nm, which is also the distance separating cross-bridge sites along ribbons. Pronounced striping at this interval is a feature of ribbon faces where they are joined in bundles. Subunits in the outer layer are arranged in vertical protofilaments that are set orthogonally to the long axis of the ribbon. Protofilaments bind tannic acid and are seen clearly in sectioned ribbons. Three protofilaments fit into the 15-nm longitudinal spacing. Optical diffraction patterns from ribbon images are dominated by orders of the 15-nm periodicity, including the third-order reflexions expected from protofilaments spacings. Fourth-order reflexions indicate that the ribbon core may also be structured. Ribbon face images give rise to a strong 4-nm layer line, corresponding to the vertical spacing of subunits in protofilaments. Neighbouring protofilaments are staggered by about 0.67 nm. The lattices found in ribbons are consistent with studies of cytoskeleton composition.

scholarly journals Hand Preference and Creativity of Papua University Student

2022 ◽  
Vol 8 (1) ◽  
pp. 257-262
Author(s):  
Vionita Putri ◽  
Elda Irma Jeanne Joice Kawulur ◽  
Febriza Dwiranti ◽  
Sabarita Sinuraya ◽  
Sita Ratnawati
Keyword(s):  
Hand Preference ◽  
University Student ◽  
Creative People ◽  
Left Hand ◽  
Adjective Check List ◽  
Left Handed ◽  
Males And Females ◽  
Papua Barat ◽  
The Right ◽  
Descriptive Method

Human has a preference to use their hands for various manual activities. Left-handed preference is people who tend to use their left hand to perform various manual activities, while right-handed people tend to use right-handed. Any researches show that the left-handed preference for more creativity was influenced by the dominant use of the right brain and bigger corpus callosum. The research aims to determine the percentage of left-handed preference and their creativity in Universitas Papua, Manokwari Papua Barat. The method used in this research is the descriptive method. Data collection used a questionnaire to evaluate individual hand preference using Handedness Questionnaire and to determine individual creativity using Adjective Check List. The percentage of left-handed people in UNIPA were 9.3% or lower than right-handed and higher than ambidextrous. Our study supports the statement about selection in handedness in the traditional society which showed a higher percentage of left-hander as advantages related to using hand intensively.  The percentage of left-handed males and females was almost equal and strongly left-handed was higher in females. The percentage of creative people was higher in left-handed, especially in males

Left-handed helical structure of poly[d(A-C)].cntdot.poly[d(G-T)] studied by infrared spectroscopy

Biochemistry ◽  
1984 ◽  
Vol 23 (24) ◽  
pp. 5703-5706 ◽  
Author(s):  
E. Taillandier ◽  
J. A. Taboury ◽  
S. Adam ◽  
J. Liquier
Keyword(s):  
Infrared Spectroscopy ◽  
Helical Structure ◽  
Left Handed
Sign in / Sign up

Export Citation Format

Share Document