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[Interaction between a fluorescent probe and the surface structures of Escherichia coli]
Biofizika
|July 1, 1977
Summary
Calcium ions (Ca2+) influence the binding of ANS fluorescent probe to Escherichia coli membranes, particularly at low temperatures. This interaction alters membrane structure and fluorescence properties.
Area of Science:
- Microbiology
- Biochemistry
- Biophysics
Background:
- The fluorescent probe 8-anilino-1-naphthalenesulfonic acid (ANS) is used to study membrane properties.
- Calcium ions (Ca2+) are known to affect bacterial cell membrane structure and function.
Purpose of the Study:
- To investigate the interaction of ANS with various components of Escherichia coli (E. coli) cells.
- To determine the effect of Ca2+ on ANS binding and fluorescence properties in E. coli.
Main Methods:
- Spectrofluorometry was used to measure ANS fluorescence intensity.
- Experiments were conducted on intact E. coli cells, isolated cell walls, total cell envelopes, and inner membranes.
- The influence of Ca2+ ions at different temperatures was examined.
Main Results:
- Ca2+ addition to intact E. coli cells at 2°C increased ANS fluorescence intensity.
- Ca2+ caused a two-fold increase in fluorescence with membrane preparations.
- A four-fold increase in quantum yields was observed, with saturation kinetics in the presence of Ca2+.
Conclusions:
- Ca2+ significantly alters the structural properties of E. coli membranes, affecting ANS binding and fluorescence.
- These structural changes induced by Ca2+ may correlate with observed biological effects in E. coli.