Studying the Forms of the Glucose Enzyme II in E. coli
Author Information
Author(s): Aboulwafa Mohammad Saier, Milton H. Jr. Saier
Primary Institution: University of California at San Diego
Hypothesis
The glucose Enzyme II transporter complex of E. coli exists in distinct physical forms that can be characterized through various methods.
Conclusion
The study provides evidence for interconvertible physical forms of the glucose Enzyme II complex in E. coli, including dimeric and monomeric structures.
Supporting Evidence
- The glucose Enzyme II complex exists in both membrane-integrated and cytoplasmic forms.
- Fluorescence energy transfer showed that the dimeric form is stable but can dissociate in the presence of detergent.
- NMR analyses indicated that the dimeric form is primarily in a lipid bilayer while the monomeric form is in micelles.
- Formaldehyde crosslinking studies revealed differential sensitivity of the enzyme forms to inactivation.
- Dynamic light scattering confirmed size differences between the dimeric and monomeric forms.
Takeaway
Scientists found that a sugar transporter in E. coli can exist in different shapes, and they used special techniques to study these shapes.
Methodology
The study used fluorescence energy transfer, formaldehyde crosslinking, cryo-electron microscopy, dynamic light scattering, and NMR spectroscopy to analyze the enzyme forms.
Limitations
The study may not account for all environmental factors affecting enzyme behavior in vivo.
Digital Object Identifier (DOI)
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