Structure of Supramers Formed by the Amphiphile Biotin-CMG-DOPE

Area of Science:

• Biochemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Biotin-CMG-DOPE is a synthetic function-spacer-lipid (FSL) amphiphile used for cell ligation.
• Its unique "apolar-polar-hydrophobic" gemini structure suggests non-classical supramolecular organization.

Purpose of the Study:

• To investigate the supramolecular organization of biotin-CMG-DOPE.
• To understand how biotin residues are presented for streptavidin binding.

Main Methods:

• Experimental methods (e.g., size measurements).
• Molecular dynamics simulations (MDS).

Main Results:

• Biotin-CMG-DOPE forms supramer globules (14.6 nm) rather than micelles.
• The DOPE tails form a hydrophobic core, while the CMG spacer folds, sequestering most biotin residues internally.
• MDS showed <10% of biotin residues are exposed on globules and 1% in coatings.

Conclusions:

• The internal sequestration of biotin residues explains their continued ability to bind streptavidin.
• This unique organization is crucial for the efficacy of biotin-CMG-DOPE in biological applications.