Structural Analysis of Glycosaminoglycans—An Indispensable Tool for the Diagnosis, Treatment and Prevention of Human Disease

2016 ◽  
pp. 38-74
2020 ◽  
pp. jbc.RA120.015305
Author(s):  
Renuka Kadirvelraj ◽  
Jeong-Yeh Yang ◽  
Hyun Woo Kim ◽  
Justin H. Sanders ◽  
Kelley W. Moremen ◽  
...  

Poly-N-acetyl-lactosamine (poly-LacNAc) structures are composed of repeating [-Galβ(1,4)-GlcNAcβ(1,3)-]n glycan extensions. They are found on both N- and O­-glycoproteins and glycolipids, and play an important role in development, immune function, and human disease. The majority of mammalian poly-LacNAc is synthesized by the alternating iterative action of β1,3-N-acetylglucosaminyltransferase 2 (B3GNT2) and β1,4-galactosyltransferases. B3GNT2 is in the largest mammalian glycosyltransferase family, GT31, but little is known about the structure, substrate recognition, or catalysis by family members. Here we report the structures of human B3GNT2 in complex with UDP:Mg2+, and in complex with both UDP:Mg2+ and a glycan acceptor, lacto-N-neotetraose. The B3GNT2 structure conserves the GT-A fold and the DxD motif that coordinates a Mg2+ ion for binding the UDP-GlcNAc sugar donor. The acceptor complex shows interactions with only the terminal Galβ(1,4)-GlcNAcβ(1,3)- disaccharide unit, which likely explains the specificity for both N- and O-glycan acceptors. Modeling of the UDP-GlcNAc donor supports a direct displacement inverting catalytic mechanism. Comparative structural analysis indicates that nucleotide sugar donors for GT-A fold glycosyltransferases bind in similar positions and conformations without conserving interacting residues, even for enzymes that use the same donor substrate. In contrast, the B3GNT2 acceptor binding site is consistent with prior models suggesting that the evolution of acceptor specificity involves loops inserted into the stable GT-A fold. These observations support the hypothesis that GT-A fold glycosyltransferases employ co-evolving donor, acceptor, and catalytic subsite modules as templates to achieve the complex diversity of glycan linkages in biological systems.


2021 ◽  
Author(s):  
Lyle R Petersen ◽  
Duane J. Gubler ◽  
Daniel R Kuritzkes

Human infection by zoonotic viruses—pathogens that normally infect animals—may result in no obvious illness, a nonspecific viral syndrome, or more severe illness typically characterized by hemorrhagic fever, encephalitis, or rash arthralgia. Transmission usually occurs by direct contact with or a bite from an infected animal or arthropod. Viral families discussed include Flaviviridae, Bunyaviridae, Arenaviridae, Filoviridae, Togaviridae, Rhabdoviridae, Paramyxoviridae, and Reoviridae, with consideration given to the epidemiology, diagnosis, treatment, and prevention of specific viruses. Hemorrhagic fevers addressed include dengue fever, dengue hemorrhagic fever, yellow fever, Crimean-Congo hemorrhagic fever, and Rift Valley fever; hantavirus infections; and the Marburg and Ebola viruses. Encephalitic fever–causing viruses discussed include La Crosse; Japanese; Murray Valley; St. Louis; tick-borne; West Nile; Powassan; eastern, western, and Venezuelan equine; rabies; Nipah; Barmah Forest; and Colorado tick fever. Rash arthralgia may be caused by the Barmah Forest, Chikungunya, Mayaro, O’nyong-nyong, Ross River, and dengue viruses. Other viral zoonoses considered include monkey B virus, ruminant and primate poxvirus, Newcastle, and foot-and-mouth diseases, as well as vesicular stomatitis virus infection. A diagram depicts the generalized arbovirus maintenance cycle. Tables list the important viral zoonoses that cause human disease, the principal hantaviruses that cause human disease, the arenaviruses that cause significant human illness, and the viral zoonoses endemic in the United States.  This review contains 1 figure, 32 tables, and 80 references. Key words: dengue, diagnosis, encephalitis, epidemic, epidemiology, infection, rabies, virus, vaccine


2021 ◽  
Vol 12 ◽  
Author(s):  
Alejandro Correa Rojo ◽  
Dries Heylen ◽  
Jan Aerts ◽  
Olivier Thas ◽  
Jef Hooyberghs ◽  
...  

Precision medicine as a framework for disease diagnosis, treatment, and prevention at the molecular level has entered clinical practice. From the start, genetics has been an indispensable tool to understand and stratify the biology of chronic and complex diseases in precision medicine. However, with the advances in biomedical and omics technologies, quantitative proteomics is emerging as a powerful technology complementing genetics. Quantitative proteomics provide insight about the dynamic behaviour of proteins as they represent intermediate phenotypes. They provide direct biological insights into physiological patterns, while genetics accounting for baseline characteristics. Additionally, it opens a wide range of applications in clinical diagnostics, treatment stratification, and drug discovery. In this mini-review, we discuss the current status of quantitative proteomics in precision medicine including the available technologies and common methods to analyze quantitative proteomics data. Furthermore, we highlight the current challenges to put quantitative proteomics into clinical settings and provide a perspective to integrate proteomics data with genomics data for future applications in precision medicine.


Author(s):  
Hannah R. Brown ◽  
Anthony F. Nostro ◽  
Halldor Thormar

Subacute sclerosing panencephalitis (SSPE) is a slowly progressing disease of the CNS in children which is caused by measles virus. Ferrets immunized with measles virus prior to inoculation with the cell associated, syncytiogenic D.R. strain of SSPE virus exhibit characteristics very similar to the human disease. Measles virus nucleocapsids are present, high measles antibody titers are found in the sera and inflammatory lesions are prominent in the brains. Measles virus specific immunoglobulin G (IgG) is present in the brain,and IgG/ albumin ratios indicate that the antibodies are synthesized within the CNS.


Author(s):  
W. H. Wu ◽  
R. M. Glaeser

Spirillum serpens possesses a surface layer protein which exhibits a regular hexagonal packing of the morphological subunits. A morphological model of the structure of the protein has been proposed at a resolution of about 25 Å, in which the morphological unit might be described as having the appearance of a flared-out, hollow cylinder with six ÅspokesÅ at the flared end. In order to understand the detailed association of the macromolecules, it is necessary to do a high resolution structural analysis. Large, single layered arrays of the surface layer protein have been obtained for this purpose by means of extensive heating in high CaCl2, a procedure derived from that of Buckmire and Murray. Low dose, low temperature electron microscopy has been applied to the large arrays.As a first step, the samples were negatively stained with neutralized phosphotungstic acid, and the specimens were imaged at 40,000 magnification by use of a high resolution cold stage on a JE0L 100B. Low dose images were recorded with exposures of 7-9 electrons/Å2. The micrographs obtained (Fig. 1) were examined by use of optical diffraction (Fig. 2) to tell what areas were especially well ordered.


Author(s):  
E. Loren Buhle ◽  
Pamela Rew ◽  
Ueli Aebi

While DNA-dependent RNA polymerase represents one of the key enzymes involved in transcription and ultimately in gene expression in procaryotic and eucaryotic cells, little progress has been made towards elucidation of its 3-D structure at the molecular level over the past few years. This is mainly because to date no 3-D crystals suitable for X-ray diffraction analysis have been obtained with this rather large (MW ~500 kd) multi-subunit (α2ββ'ζ). As an alternative, we have been trying to form ordered arrays of RNA polymerase from E. coli suitable for structural analysis in the electron microscope combined with image processing. Here we report about helical polymers induced from holoenzyme (α2ββ'ζ) at low ionic strength with 5-7 mM MnCl2 (see Fig. 1a). The presence of the ζ-subunit (MW 86 kd) is required to form these polymers, since the core enzyme (α2ββ') does fail to assemble into such structures under these conditions.


Author(s):  
Paul DeCosta ◽  
Kyugon Cho ◽  
Stephen Shemlon ◽  
Heesung Jun ◽  
Stanley M. Dunn

Introduction: The analysis and interpretation of electron micrographs of cells and tissues, often requires the accurate extraction of structural networks, which either provide immediate 2D or 3D information, or from which the desired information can be inferred. The images of these structures contain lines and/or curves whose orientation, lengths, and intersections characterize the overall network.Some examples exist of studies that have been done in the analysis of networks of natural structures. In, Sebok and Roemer determine the complexity of nerve structures in an EM formed slide. Here the number of nodes that exist in the image describes how dense nerve fibers are in a particular region of the skin. Hildith proposes a network structural analysis algorithm for the automatic classification of chromosome spreads (type, relative size and orientation).


Sign in / Sign up

Export Citation Format

Share Document