Faculty Opinions recommendation of Topologically Constrained Formation of Stable Z-DNA from Normal Sequence under Physiological Conditions.

Abstract Left-handed Z-DNA is radically different from the most common right-handed B-DNA and can be stabilized by interactions with the Zα domain, which is found in a group of proteins, such as human ADAR1 and viral E3L proteins. It is well-known that most Zα domains bind to Z-DNA in a conformation-specific manner and induce rapid B–Z transition in physiological conditions. Although many structural and biochemical studies have identified the detailed interactions between the Zα domain and Z-DNA, little is known about the molecular basis of the B–Z transition process. In this study, we successfully converted the B–Z transition-defective Zα domain, vvZαE3L, into a B–Z converter by improving B-DNA binding ability, suggesting that B-DNA binding is involved in the B–Z transition. In addition, we engineered the canonical B-DNA binding protein GH5 into a Zα-like protein having both Z-DNA binding and B–Z transition activities by introducing Z-DNA interacting residues. Crystal structures of these mutants of vvZαE3L and GH5 complexed with Z-DNA confirmed the significance of conserved Z-DNA binding interactions. Altogether, our results provide molecular insight into how Zα domains obtain unusual conformational specificity and induce the B–Z transition.

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Poly(amino2dA-dT) Isomerizes into the Unusual X-DNA Double Helix at Physiological Conditions Inducing Z-DNA in Poly(dG-methyl5dC)

Journal of Biomolecular Structure and Dynamics ◽

10.1080/07391102.1988.10506503 ◽

1988 ◽

Vol 6 (3) ◽

pp. 503-510 ◽

Cited By ~ 20

Author(s):

Michaela Vorlickova ◽

Janos Sagi ◽

Anna Szabolcs ◽

Attila Szemzo ◽

Laszlo Otvos ◽

...

Keyword(s):

Double Helix ◽

Physiological Conditions ◽

Z Dna ◽

Dna Double Helix

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Ultrastructure of Giant Mitochondria and Their Inclusions in Schwann Cells of Bovine Splenic Nerve

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100050986 ◽

1974 ◽

Vol 32 ◽

pp. 194-195

Author(s):

Å. Thureson-Klein

Keyword(s):

Schwann Cells ◽

Cell Organelles ◽

Giant Mitochondria ◽

Matrix Density ◽

Physiological Conditions ◽

Unmyelinated Axons ◽

Internal Structures ◽

Structural Abnormalities ◽

Cytotoxic Compounds ◽

Cell Components

Giant mitochondria of various shapes and with different internal structures and matrix density have been observed in a great number of tissues including nerves. In most instances, the presence of giant mitochondria has been associated with a known disease or with abnormal physiological conditions such as anoxia or exposure to cytotoxic compounds. In these cases degenerative changes occurred in other cell organelles and, therefore the giant mitochondria also were believed to be induced structural abnormalities.Schwann cells ensheating unmyelinated axons of bovine splenic nerve regularly contain giant mitochondria in addition to the conventional smaller type (Fig. 1). These nerves come from healthy inspected animals presumed not to have been exposed to noxious agents. As there are no drastic changes in the small mitochondria and because other cell components also appear reasonably well preserved, it is believed that the giant mitochondria are normally present jin vivo and have not formed as a post-mortem artifact.

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Freeze-fracture observations on changes in the distribution of Filipin-sterol complexes during epididymal maturation and capacitation of boar spermatozoa

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100157991 ◽

1990 ◽

Vol 48 (3) ◽

pp. 90-91

Author(s):

N. Seki ◽

Y. Toyama ◽

T. Nagano

Keyword(s):

Plasma Membrane ◽

Essential Role ◽

Freeze Fracture ◽

Final Concentration ◽

Freeze Fracturing ◽

Physiological Conditions ◽

Epididymal Maturation ◽

Cacodylate Buffer ◽

Sperm Membrane ◽

Boar Spermatozoa

It is believed that i ntramembra.nous sterols play an essential role in membrane stability and permeability. To investigate the distribution changes of sterols in sperm membrane during epididymal maturation and capacitation, filipin has been used as a cytochemical probe for the detection for membrane sterols. Using this technique in combination with freeze fracturing, we examined the boar spermatozoa under various physiological conditions.The spermatozoa were collected from: 1) caput, corpus and cauda epididymides, 2) sperm rich fraction of ejaculates, and 3)the uterus 2hr after natural coition. They were fixed with 2.5% glutaraldehyde in 0.05M cacodylate buffer (pH 7.4), and treated with the filipin solution (final concentration : 0.02.0.05%) for 24hr at 4°C with constant agitation. After the filipin treatment, replicas were made by conventional freeze-fracture technique. The density of filipin-sterol complexes (FSCs) was determined in the E face of the plasma membrane of head regions.

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