Home Hydration Analogs Hydration Bridging Hydrophobic Surfaces Coil Formation
Beta-Sheet Formation Beta-Turn Formation Carboxypeptidase A Assembly References












Download PDF of this page   Download PDF Book  Hydrophobic Surfaces

Hydration Bridging and Linear Hydration Element Formation

II - Point-Charge and Covalent Hydrogen Bonding

Hydrogen bonding between surface water and natural polypeptides, as they emerge from exit channels in ribosomes, provides for both stability and instability in chains. Point-charge hydrogen bonding of dynamic surface water with connecting amides, small polar peptides and polar and ionic groups, moves energy into chains while water, in forming unstable covalently-bonds (white) in linear elements adjacent to non-hydrogen-bonding methylenes and methyls in side chains, imposes instability and drives chains into coils and assembles them together to form stable proteins.4,6,13

Although covalent linear bonds last only 10-11 seconds and are difficult to identify, by losing energy to surrounding water as they form and removing energy from lipid regions as they decay, short linear elements of no more than five or six water molecules impose destabilizing order on those regions and drive them into coils or bind them together to reduce order in surface water. By spontaneously moving from order toward disorder, surface water moves natural polypeptides from randomness toward order.24

At the same time, dynamic point-charge bonding of surface water to polar and ionic regions transfers energy into them to increase mobility and stability. Alcoholic side chains of serines and threonines hydrogen bond with surface water to increase entropy, solubility and stability. Glycines, with only two hydrogens on alpha carbons, absorb energy from surface water to rotate around their carbon bonds. Prolines, with five-membered rings and no amide hydrogen, force turns in chains but induce covalent bonding in water adjacent to their three methylenes.

Ionic peptides, like glutamic acid and lysine, induce the formation of transient dielectric hydration bridging between them to draw them together and provide for proton transfer, charge stabilization and counter-ion formation.26,28

Transient covalent linear elements of water molecules bridge beween peptides on surfaces of polypetides as they are released from ribosomes.