Towards a Better Understanding of Computational Models for Predicting DNA Methylation Effects at the Molecular Level

2020 ◽  
Vol 20 (10) ◽  
pp. 901-909
Author(s):  
Nathanael K. Proctor ◽  
Tugba Ertan-Bolelli ◽  
Kayhan Bolelli ◽  
Ethan W. Taylor ◽  
Norman H.L. Chiu ◽  
...  

Human DNA is a very sensitive macromolecule and slight changes in the structure of DNA can have disastrous effects on the organism. When nucleotides are modified, or changed, the resulting DNA sequence can lose its information, if it is part of a gene, or it can become a problem for replication and repair. Human cells can regulate themselves by using a process known as DNA methylation. This methylation is vitally important in cell differentiation and expression of genes. When the methylation is uncontrolled, however, or does not occur in the right place, serious pathophysiological consequences may result. Excess methylation causes changes in the conformation of the DNA double helix. The secondary structure of DNA is highly dependent upon the sequence. Therefore, if the sequence changes slightly the secondary structure can change as well. These slight changes will then cause the doublestranded DNA to be more open and available in some places where large adductions can come in and react with the DNA base pairs. Computer models have been used to simulate a variety of biological processes including protein function and binding, and there is a growing body of evidence that in silico methods can shed light on DNA methylation. Understanding the anomeric effect that contributes to the structural and conformational flexibility of furanose rings through a combination of quantum mechanical and experimental studies is critical for successful molecular dynamic simulations.

2021 ◽  
Vol 8 (10Years) ◽  
pp. 51-73
Author(s):  
Weliton Batiston ◽  
Emanuel Carrilho

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.


2020 ◽  
Vol 9 (2) ◽  
pp. 53
Author(s):  
Yao Yao

<p>Prion is a protein smaller than virus and it infects host in the absence of nucleic acid. The secondary structure of protein folds incorrectly from α-helices to β-sheets through breaking and re-formation of hydrogen bond. Structural analogy of α-helix and DNA double helix and comparing differences between α-helix and β-sheet show prion's infectivity and propagation. Aggregates of dimers and polymers generate β-amyloid fibril in Alzheimer's disease.</p>


1999 ◽  
Vol 13 (28) ◽  
pp. 999-1003 ◽  
Author(s):  
HAIJUN ZHOU ◽  
ZHONG-CAN OU-YANG

The folding angle distribution of stretched and negatively supercoiled DNA double-helix is investigated based on a previously proposed model of double-stranded biopolymers [H. Zhou et al., Phys. Rev. Lett.82, 4560 (1999)]. It is shown that pulling can cause transition of a negatively supercoiled DNA double-helix from the right-handed B-form to a left-handed configuration which resembles DNA Z-form in some important aspects. The energetics of this possible transition is calculated and a comparison with recent experimental observations is qualitatively discussed.


Author(s):  
D.P. Bazett-Jones ◽  
F.P. Ottensmeyer

Dark field electron microscopy has been used for the study of the structure of individual macromolecules with a resolution to at least the 5Å level. The use of this technique has been extended to the investigation of structure of interacting molecules, particularly the interaction between DNA and fish protamine, a class of basic nuclear proteins of molecular weight 4,000 daltons.Protamine, which is synthesized during spermatogenesis, binds to chromatin, displaces the somatic histones and wraps up the DNA to fit into the small volume of the sperm head. It has been proposed that protamine, existing as an extended polypeptide, winds around the minor groove of the DNA double helix, with protamine's positively-charged arginines lining up with the negatively-charged phosphates of DNA. However, viewing protamine as an extended protein is inconsistent with the results obtained in our laboratory.


2019 ◽  
Vol 316 (5) ◽  
pp. H1113-H1123 ◽  
Author(s):  
Sameed Ahmed ◽  
Rui Hu ◽  
Jessica Leete ◽  
Anita T. Layton

Sex differences in blood pressure and the prevalence of hypertension are found in humans and animal models. Moreover, there has been a recent explosion of data concerning sex differences in nitric oxide, the renin-angiotensin-aldosterone system, inflammation, and kidney function. These data have the potential to reveal the mechanisms underlying male-female differences in blood pressure control. To elucidate the interactions among the multitude of physiological processes involved, one may apply computational models. In this review, we describe published computational models that represent key players in blood pressure regulation, and highlight sex-specific models and their findings.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yan Xue ◽  
Zhenhui Zhong ◽  
C. Jake Harris ◽  
Javier Gallego-Bartolomé ◽  
Ming Wang ◽  
...  

AbstractThe Microrchidia (MORC) family of ATPases are required for transposable element (TE) silencing and heterochromatin condensation in plants and animals, and C. elegans MORC-1 has been shown to topologically entrap and condense DNA. In Arabidopsis thaliana, mutation of MORCs has been shown to reactivate silent methylated genes and transposons and to decondense heterochromatic chromocenters, despite only minor changes in the maintenance of DNA methylation. Here we provide the first evidence localizing Arabidopsis MORC proteins to specific regions of chromatin and find that MORC4 and MORC7 are closely co-localized with sites of RNA-directed DNA methylation (RdDM). We further show that MORC7, when tethered to DNA by an artificial zinc finger, can facilitate the establishment of RdDM. Finally, we show that MORCs are required for the efficient RdDM mediated establishment of DNA methylation and silencing of a newly integrated FWA transgene, even though morc mutations have no effect on the maintenance of preexisting methylation at the endogenous FWA gene. We propose that MORCs function as a molecular tether in RdDM complexes to reinforce RdDM activity for methylation establishment. These findings have implications for MORC protein function in a variety of other eukaryotic organisms.


Author(s):  
Matthew Devall ◽  
Xiangqing Sun ◽  
Fangcheng Yuan ◽  
Gregory S Cooper ◽  
Joseph Willis ◽  
...  

Abstract There are well-documented racial differences in age-of-onset and laterality of colorectal cancer. Epigenetic age acceleration is postulated to be an underlying factor. However, comparative studies of side-specific colonic tissue epigenetic aging are lacking. Here, we performed DNA methylation analysis of matched right and left biopsies of normal colon from 128 individuals. Among African Americans (n = 88), the right colon showed accelerated epigenetic aging as compared to individual-matched left colon (1.51 years; 95% CI = 0.62 to 2.40 years; two-sided P = .001). In contrast, among European Americans (n = 40), the right colon shows remarkable age deceleration (1.93 years; 95% CI = 0.65 to 3.21 years; two-sided P = .004). Further, epigenome-wide analysis of DNA methylation identifies a unique pattern of hypermethylation in African American right colon. Our study is the first to report such race and side-specific differences in epigenetic aging of normal colon, providing novel insight into the observed younger age-of-onset and relative preponderance of right-side colon neoplasia in African Americans.


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