The effect of lysozyme on DNA-Membrane association in Escherichia coli

Samuel Silberstein, Masa Yori Inouye

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

The chromosome of Escherichia coli sediments three different ways in sucrose density gradients, depending upon the concentration of lysozyme used to lyse the cells, as follows: 1. (1) Low-S complex. In the presence of 2-400 μg/ml of egg white lysozyme with Brij-58-Na deoxycholate or Triton X-100, the chromosome sediments at 500-1100 S (low-S complex). When Brij-58 alone is used, some of the DNA sediments as a low-S complex and some sediments rapidly with the membrane fraction. 2. (2) Secondary DNA-membrane complex. In the presence of 800 μg/ml of egg white lysozyme, all the DNA sediments with the membrane fraction at greater than 4000 S regardless of which detergent is used. This DNA-membrane complex is due to the high concentration of lysozyme, for when a pre-formed low-S complex is exposed to a high concentration of lysozyme, it sediments with the membrane fraction. This association can also be seen in the presence of poly(l-lysine), ribonuclease, Mg2+ or spermidine, indicating that lysozyme mediates the DNA-membrane association non-specifically as a polycation. An artificial association between exogenous coalfish DNA and an E. coli membrane fraction is induced by 800 μg/ml of lysozyme. 3. (3) Primary DNA-membrane complex. A concentration of T4 lysozyme as low as 0.01 μg/ml, or 20 lysozyme molecules/chromosome, can lyse cells. This is in contrast to 2 · 106 lysozyme molecules/chromosome corresponding to 800 μg/ml of egg white lysozyme. Under these mild lysis conditions, the chromosome sediments with the membrane fraction, suggesting a primary DNA-membrane association.

Original languageEnglish (US)
Pages (from-to)149-158
Number of pages10
JournalBBA Section Nucleic Acids And Protein Synthesis
Volume366
Issue number2
DOIs
StatePublished - Oct 11 1974
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Medicine(all)

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