Related Experiment Video
Updated: Sep 14, 2026

In Situ Characterization of Hydrated Proteins in Water by SALVI and ToF-SIMS
Published on: February 15, 2016
Evidence for the presence of water within the hydrophobic core of membranes
E M Meier1, D Schummer, K Sandhoff
1Institute of Organic Chemistry and Biochemistry, University of Bonn, F.R.G.
Abstract:
The photoreactive ganglioside derivative N-diazirinyl-lyso-GM1 was incorporated into liposomes and calf brain microsomes. After photoactivation at 350 nm it was found to dimerize with phospholipids such as phosphatidylcholine and phosphatidylserine and with cholesterol. The predominant covalent reaction product, however, was the alcohol, resulting from the reaction with water. It amounted to about 45% of the covalent reaction products in calf brain microsomes and to about 58% in pure phosphatidylcholine liposomes. Based on the temperature dependence of the photoreaction of N-diazirinyl-lyso-GM1 in liposomes consisting of 1,2-dipalmitoyl-sn-glycero-3-phosphoryl-choline or 1,2-distearoyl-sn-glycero- 3-phosphorylcholine and on affinity labeling experiments with cholera toxin we propose that the predominant reaction of N-diazirinyl-lyso-GM1 with water is due to the presence of water within the hydrophobic core of artificial and biological membranes.
Related Concept Videos
Membrane Fluidity
Membrane Fluidity
Mosaic nature of the membrane
The mosaic characteristic of the membrane helps the plasma membrane remain fluid. The integral proteins and lipids exist as separate but loosely-attached molecules in the membrane. The membrane is a relatively...
Fluid Mosaic Model
Membrane Domains
Protein Domains
The membrane comprises a group of distinct proteins responsible for carrying out a cell's specific function. For example, the plasma membrane of the human sperm, or a single germ cell, contains a unique set of proteins in the anterior...
Aquaporins
Membrane Lipids
Phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and sphingomyelin are the most common phospholipids present in mammalian membranes. At physiological pH, phosphatidylserine is negatively charged, while the other three...

