Protein interaction with ions

Tn nature proteins interact with ions, lipids, and other proteins as part of the broad spectrum of necessary biological processes including membrane functionality and antigen-antibody effects. Protein functionality can be altered greatly by the interaction of proteins with surface-active agents, and the subject of protein-surfactant interaction is important in relation to food, cosmetic, and biomedical areas. 

Other studies included the investigation of the stabilizing effect of sorbitol on hen egg white lysozyme and the use of the self-diffusion coefficient, D, to follow the solution and aggregative properties of lysozyme at different pH, temperature, and protein and salt concentrations. The properties of frozen ovalbumin solutions were studied by NMR relaxation spectroscopy. It is known that the functional properties of muscle proteins are affected by protein interactions with ions, and NMR was used to assess protein/water, protein/salt, and protein/protein interactions in myofibrillar protein solutions. Previous X-ray and NMR studies on collagen and peptides were reviewed by Mayo and, more recently, such types of system were characterized by high-resolution H and C NMR. °0 The structure, hydration state, and nature of the interactions between water and gelatin were determined by time domain NMR. ... 

Biomolecules interact with one another through molecular surfaces that are structurally complementary. How can various proteins interact with molecules as different as simple ions, hydrophobic lipids, polar but uncharged carbohydrates, and even nucleic acids ... 

Proteins closely related to spectrin and ankyrin and many of the associated proteins first identified in erythrocytes also are prevalent in most vertebrate tissues. In these other tissues, spectrin and ankyrin and their associated proteins interact with proteins that may not be expressed in erythrocytes, including ion channel... 

Taste receptor cells are organized into taste buds 825 Sensory afferents within three cranial nerves innervate the taste buds 826 Information coding of taste is not strictly according to a labeled line 826 Taste cells have multiple types of ion channels 826 Salts and acids are transduced by direct interaction with ion channels 826 Taste cells contain receptors, G proteins and second-messenger-effector enzymes 827... 

Transcription factors must recognize and bind to specific target DNA sequences located in promoters and enhancers. They must also activate transcription. The parts of the protein that are involved in these different functions usually lie in physically independent domains. There are many types of DNA-binding domains. Perhaps the best understood are the zinc lingers, in which a small group of conserved amino acids binds a zinc ion. The activation domains are less well understood. It is thought that they are involved in protein/protein interaction with other transcription factors and/or RNA polymerase. 

The mechanism whereby pyrethroids interact with ion channels is not yet understood, since their high lipophylicity makes investigation difficult, but type II pyrethroids have been shown to directly stimulate protein kinase C-dependent protein-phosphorylation at very low concentrations. Since ion channel activity is modulated by phosphorylation state, this is likely to be an important mechanism of action. 

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