Cell surface-located deoxyribonucleic acid receptors in transformable pneumococci. Academic Article uri icon

Overview

abstract

  • We studied deoxyribonucleic acid (DNA) binding in transformable pneumococci. The relevant findings are as follows. (i) At least half of the DNA Molecules adsorbed to competent cells in the growth medium are attached to sites on the protoplast membrane. (ii) Most of the DNA bound to live competent cells in the presence of glucose is not released by moderate shear or by autolysin treatment. In contrast, most of the DNA adsorbed to competent cells in the absence of glucose is shear and autolysin sensitive. (iii) The presence of binding sites resembling in properties the sites in live competent cells can be demonstrated in wall-membrane complexes. Most of these sites are lost during preparation of cell walls and protoplasts. It is suggested that the DNA-binding site is a membrane component (protein?) Stabilized by polysaccharide (cell Wall) material. (IV) Mechanical or enzymatic damage to the cell wall or change in the ionic conditions can induce DNA binding (and surface-nuclease activity) in the incompetent pneumococci. However, such cells still show neither genetic transformation nor extensive nuclease-resistant binding of DNA. It is suggested that both competent and incompetent cells contain a large number of sequestered DNA-binding sites that can be unmasked by several experimental conditions. Induction of the competent state by the competence activator protein may involve an endogenous unmasking process.

publication date

  • June 1, 1975

Research

keywords

  • DNA, Bacterial
  • Streptococcus pneumoniae

Identity

PubMed Central ID

  • PMC246191

Scopus Document Identifier

  • 0016815681

Digital Object Identifier (DOI)

  • 10.1128/jb.122.3.1339-1350.1975

PubMed ID

  • 238945

Additional Document Info

volume

  • 122

issue

  • 3