Probing DNA quaternary ordering with circular dichroism spectroscopy: Studies of equine sperm chromosomal fibers

  title={Probing DNA quaternary ordering with circular dichroism spectroscopy: Studies of equine sperm chromosomal fibers},
  author={Mary L. Sipski and Thomas E. Wagner},
Studies are described which strongly support a cholesteric liquid crystal‐like quaternary structure for the DNA molecules of a biologically native chromosomal preparation from equine sperm cells. Discrete chromosomal fibers released from the head pieces of equine spermatozoon cells were prepared intact and probed for liquid crystalline ordering using reflectance and linear dichroism spectroscopy. Assuming cholesteric liquid crystalline order for the DNA molecules within the chromatin fibers… Expand
31 Citations
Subunit structure of Eutherian sperm chromatin.
Data from nuclease digestion studies in conjunction with electron microscopic evidence indicate that the gross structure of the unit Eutherian sperm chromosomal fiber consists of DNA folded around sperm specific histone multimers spaced regularly along the fiber generating a linear array of sperm nucleosomes connected by short stretches of uncomplexed DNA. Expand
Ordered phases of DNA in vivo and in vitro
In vitro, pure DNA forms multiple liquid crystalline phases when the polymer concentration is increased: precholesteric organization, cholesteric phase and columnar hexagonal phase. SimilarExpand
Cholesteric organization of DNA in the stallion sperm head.
The fine structure of chromatin in sperm heads was investigated by different microscopic techniques: in vivo examinations in the polarizing microscope, thin sections and freeze-fracture replicas observed by transmission electron microscopy, which presented a new interpretation of this lamellated aspect. Expand
DNA and protein content of mouse sperm. Implications regarding sperm chromatin structure.
It is shown that the DNA in the mouse sperm nucleus cannot be packaged in nucleosomes, and the protamines in sperm chromatin do not function as structural proteins, providing a subunit core around which the DNA is wrapped, but appear to completely neutralize the phosphodiester backbone of the DNA molecule. Expand
A DSC study of the liquid crystalline phases of salmon sperm DNA
Abstract Thermodynamic stabilities of the liquid crystalline (LC) and gel (G) phases of salmon sperm DNA were investigated by differential scanning calorimetry (DSC). The enthalpic and the entropicExpand
Multiple liquid crystal phases of DNA at high concentrations
It is found that DNA forms at least three distinct liquid crystalline phases at concentrations comparable to those in vivo, with phase transitions occurring over relatively narrow ranges of DNA concentration. Expand
Twisted liquid crystalline supramolecular arrangements in morphogenesis.
It appears that the building of cellular and extracellular edifices implies self-ordering processes of the liquid crystalline type and that the study of these mesomorphic states will help resolve basic questions about the structure and morphogenesis of densely packed biological structures. Expand
Structural polymorphism of liquid-crystalline dispersions of double-stranded DNA complexed with synthetic polycations
Linear double-stranded DNA molecules interact with positively charged polyconidine molecules in aqueous salt solutions to yield liquid-crystalline dispersions (LCDs) with a mean particle diameter ofExpand
Circular Dichroism of DNA, Proteins and Chromatin
Although great strides have been made towards the elucidation of the structure of chromatin, many details remain unanswered as to the manner in which DNA is folded and condensed in the nucleus. TheExpand
Condensation of DNA by the C-terminal domain of histone H1. A circular dichroism study.
It is concluded that the condensation of DNA mediated by histone H1 is mainly due to its C-terminal domain, which is characterized by a nonconservative circular dichroism spectrum which is currently attributed to ordered aggregation of the DNA molecules. Expand


The role of disulfide reduction in chromatin release from equine sperm.
The induced expulsion of a condensed chromosomal strand from equine sperm head pieces by the combined action of guanidine HCl and β-mercaptoethanol is documented by scanning electron microscopy and the circular dichroism spectrum of a disordered gel state suggests that the DNA component of this chromosomal material may be in the compact ψ-DNA state. Expand
The structure of ψ DNA
Abstract In concentrated solutions of neutral or anionic polymers (and an adequate cation concentration), DNA condenses into a compact state, which is of interest for its possible relevance toExpand
A super-coil model for nucleohistone.
X-ray diffraction from fibre and gel specimens of nucleohistone include lowangle diffraction that is not given by DNA or histone alone, and the relation between the supercoil and structures observed in the electron microscope is discussed. Expand
Super-helical Model for Nucleohistone
A coiled-coil structure for nucleohistone is discussed and new experimental evidence that is compatible with it is found that iscompatible with it. Expand
Infrared circular dichroism and linear dichroism of liquid crystals
In order to test the validity of our recently reported theory of optical activity near absorption bands of cholesteric liquid crystals, we have measured the infrared linear dichroism (LD) of theExpand
Circular dichroism and rotatory dispersion near absorption bands of cholesteric liquid crystals
A macroscopic theory is developed to explain the intense and highly structured circular dichroism (CD) and optical rotary dispersion (ORD) measurements of cholesteric liquid crystals in spectralExpand
A transition to a compact form of DNA in polymer solutions.
  • L. Lerman
  • Chemistry, Medicine
  • Proceedings of the National Academy of Sciences of the United States of America
  • 1971
In the presence of over-threshold concentrations of simple neutral polymers and salts, DNA undergoes a cooperative change in its solution structure and collapses into particles approaching the compactness of the contents of phage heads. Expand
INTRODUCTION IN this paper the remarkable properties, including the very high optical rotatory power, of a liquid crystalline phase which is formed by certain polypeptide solutions will be discussed.Expand
Alterations in Specific Gravity during the Ripening of Bull Spermatozoa
Summary Determinations of the specific density of spermatozoa in ejaculates collected from normal dairy bulls in regular service were performed by centrifugation in umbradil-methylglucamine-saltExpand
Rotatory power and other optical properties of certain liquid crystals
A group of liquid crystals, mainly derivates of cholesterol, shows remarkable optical properties, including strong rotatory power and selective reflexion of circularly polarized light in a narrowExpand