X-ray Diffraction and the Discovery of the Structure of DNA. A Tutorial and Historical Account of James Watson and Francis Crick's Use of X-ray Diffraction in Their Discovery of the Double Helix Structure of DNA

2007 ◽  
Vol 84 (5) ◽  
pp. 803 ◽  
Author(s):  
David T. Crouse
Keyword(s):  
Double Helix ◽  
Historical Account ◽  
X Ray Diffraction ◽  
X Ray ◽  
Helix Structure ◽  
Double Helix Structure

scholarly journals The Importance and Challenges for Analytical Chemistry in Proteomics Analysis

2021 ◽  
Vol 8 (10Years) ◽  
pp. 51-73
Author(s):  
Weliton Batiston ◽  
Emanuel Carrilho
Keyword(s):  
Analytical Chemistry ◽  
Double Helix ◽  
X Ray Diffraction ◽  
Proteomics Analysis ◽  
Linus Pauling ◽  
X Ray ◽  
Francis Crick ◽  
Double Helix Structure ◽  
The Right ◽  
Dna Double Helix

Although Linus Pauling had an exceptional scientific contribution to the study of chemical bonds, reported in his book The Nature of Chemical Bond, the lousy image he got for the X-ray diffraction drove him to an unstable structure with an unreal DNA triple helix publication. Oppositely, for the consecration of James Watson & Francis Crick, they had the opportunity to enter science history using the right image of X-ray to propose the famous DNA double helix structure correctly. This chapter of science is an excellent example of how analytical chemistry performance affects horizons and scientific advances. Today the complexity of the systems is more significant and understanding how all proteins truly work into cells and organisms is the current challenge from proteomics. Comprehending how analysis is carried out and how instruments work could promote new insights to improve the analytical performance in proteomics. Here we described an overview based on our expertise on the analytical chemistry toolkit for proteomics analysis: shotgun, bottom-up, middle-down, top-down, and native proteomics, and their inherent instrumentation technologies. In addition, a detailed discussion of the analytical figures of merit in proteomics analysis is provided. We also address the limitations in multidimensional liquid chromatography and tandem mass spectrometry platforms. Furthermore, we present some perspectives in bioinformatics, mathematical modeling simulations, and chemometrics tools, as well.

Design

2020 ◽  
pp. 129-141
Author(s):  
Stephen K. Reed
Keyword(s):  
Double Helix ◽  
University Of California ◽  
X Ray Diffraction ◽  
Design Problems ◽  
Goal State ◽  
Helix Structure ◽  
Intermediate States ◽  
Double Helix Structure ◽  
La Jolla ◽  
The University

Many design problems are ill-structured in which the start state, the goal state, and intermediate states are incompletely specified. They do not have right or wrong answers, only better or worse ones. They require decomposition into smaller parts that are revisited as the design progresses. Scientists also confront design problems as they search for nature’s design, such as the structure of DNA. The success of Watson and Crick in discovering its double-helix structure was influenced by their access to X-ray diffraction pictures, ability to interpret these pictures, utilize the relative amounts of bases in the molecule, and recognize that two strands of a molecule provide a mechanism for replication. The Geisel Library on the University of California, San Diego, campus illustrates the combination of function and beauty in designing a building. The Salk Institute in La Jolla, California, is widely acclaimed as a magnificent achievement by Louis Kahn. The addition of the East Building is an example of the challenges encountered in making modifications.

Light Scattering and Flow Dichroism Studies on DNA After the Photoreaction with Psoralen

1972 ◽  
Vol 27 (2) ◽  
pp. 196-200 ◽  
Author(s):  
S. Marciani ◽  
M. Terbojevic ◽  
F. Dall’Acqua
Keyword(s):  
Heat Treatment ◽  
Molecular Weight ◽  
Light Scattering ◽  
Double Helix ◽  
Heat Denaturation ◽  
Scattering Measurements ◽  
Helix Structure ◽  
Double Helix Structure

Light scattering measurements performed on DNA after irradiation in the presence of psoralen clearly show that inter strand cross linkings are present in the macromolecule. In fact after heat denaturation and successive cooling irradiated macromolecule shows a molecular weight practically unchanged while a DNA sample after the same treatment shows a molecular weight half of the intact native DNA. Also the general conformation of irradiated DNA undergoes practically to no modifications after the same heat treatment while native DNA shows itself to have been strongly modified. Moreover, on the basis of flow dichroism determinations, DNA cross-linked by psoralen after heat denaturation showed to be able to restore its ordered double helix structure, during the successive cooling.

The Effect of Crystal Packing on Oligonucleotide Double Helix Structure

1987 ◽  
Vol 5 (3) ◽  
pp. 557-579 ◽  
Author(s):  
Richard E. Dickerson ◽  
David S. Goodsell ◽  
Mary L. Kopka ◽  
Philip E. Pjura
Keyword(s):  
Crystal Packing ◽  
Double Helix ◽  
Helix Structure ◽  
Double Helix Structure

Imaging of the DNA (deoxyribonucleic acid) Double Helix Structure by Noncontact Atomic Force Microscopy

1999 ◽  
Vol 38 (Part 2, No. 11A) ◽  
pp. L1211-L1212 ◽  
Author(s):  
Yasushi Maeda ◽  
Takuya Matsumoto ◽  
Hiroyuki Tanaka ◽  
Tomoji Kawai
Keyword(s):  
Atomic Force Microscopy ◽  
Deoxyribonucleic Acid ◽  
Double Helix ◽  
Force Microscopy ◽  
Atomic Force ◽  
Helix Structure ◽  
Double Helix Structure

scholarly journals C3′ Stereocentre of Furanose Determines the Helicity of Double-Stranded Nucleic Acids: Towards Etiology of Nucleic Acids

2020 ◽  
Author(s):  
Anuj Kumar ◽  
Amol Tagad ◽  
G. Naresh Patwari
Keyword(s):  
Molecular Dynamics ◽  
Nucleic Acids ◽  
Structural Transition ◽  
Double Helix ◽  
Helical Structure ◽  
Structural Features ◽  
Toggle Switch ◽  
Helix Structure ◽  
Double Helix Structure ◽  
Dynamics Simulations

ABSTRACTRibose containing double-stranded nucleic acids exhibit helical structure, whereas sugar modified (xeno) nucleic acids may exhibit different structural features. The structural landscape of four stereo variants of furanosal nucleic acids and their C2′ deoxy counterparts, explored with molecular dynamics simulations, suggest that the configuration at the C3′ position plays a pivotal role in determining the helicity. The C3′ stereocentre acts as toggle-switch for the helix to ladder structural transformation by changing the nature of intra-strand interactions resulting in the optimal helices for ribose containing double-stranded nucleic acids. Interestingly, lack of chirality at the C2′ position results in better quality helices than inversion of stereochemistry relative to ribose. The etiology of furanosal-RNA over other furanoses can be hypothesized based on the helical structure, which can effectively be exploited by the biological machinery.SIGNIFICANCEThe double helix structure of furanosal RNA is governed by the configuration at the C3′ position. Furanose sugars such as xylose and lyxose where in the configuration at the C3′ position is inverted relative to the ribose do not form double helix structure, instead result in ladder-like structure. The configuration at the C3′ position acts as a toggle switch for the helix to ladder structural transition. Among four furanose sugars viz., ribose, arabinose, xylose, and lyxose, the double-stranded nucleic acids incorporating ribose form helices with best aspect ratio between major and minor grooves.

scholarly journals A Sensitive Fluorescence Biosensor for Silver Ions (Ag+) Detection Based on C-Ag+-C Structure and Exonuclease III-Assisted Dual-Recycling Amplification

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Yubin Li ◽  
Jiaming Yuan ◽  
Zexi Xu
Keyword(s):  
Double Helix ◽  
Silver Ions ◽  
Exonuclease Iii ◽  
Quadruplex Dna ◽  
G Quadruplex ◽  
Helix Structure ◽  
Double Helix Structure ◽  
Exo Iii ◽  
Fluorescence Biosensor ◽  
Recycling Amplification

A C-Ag+-C structure-based fluorescence biosensor with novel combination design of exonuclease III (Exo III) dual-recycling amplification is proposed for the application of silver ions (Ag+) detection. Since oligo-1 involves C-C mismatches, the presence of Ag+ can be captured to form C-Ag+-C base pairs, which results in a double-helix structure with a blunt terminus. The double-helix structure can be cleaved by EXO III to release short mononucleotide fragments (trigger DNA) and Ag+. Released Ag+ can form new bindings with oligo-1, and other trigger DNA can be produced in the digestion cycles. Hybridization with the signal DNA (oligo-2) transforms a trigger DNA into double-stranded DNA with blunt terminus which can be cleaved by Exo III to reproduce the trigger DNA and form guanine- (G-) quadruplex DNA. The trigger DNA returns free to the solution and hybridizes with another signal DNA, which realizes the dual-recycling amplification. The G-quadruplex DNA can be reported by N-methylmesoporphyrin IX (NMM), a specific G-quadruplex DNA fluorochrome. This method allows Ag+ to be determined in the 5 to 1500 pmol/L concentration range, with a 2 pmol/L detection limit, and it has been successfully applied to the detection of Ag+ in real samples.

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