Carbonyl–water hydrogen bonding: The H2CO–H2O prototype

1994 ◽  
Vol 100 (6) ◽  
pp. 4347-4354 ◽  
Author(s):  
Theresa A. Ramelot ◽  
Ching‐Han Hu ◽  
Joseph E. Fowler ◽  
Bradley J. DeLeeuw ◽  
Henry F. Schaefer
Keyword(s):  
Hydrogen Bonding ◽  
Water Hydrogen

scholarly journals Functional stability of water wire–carbonyl interactions in an ion channel

2020 ◽  
Vol 117 (22) ◽  
pp. 11908-11915 ◽  
Author(s):  
Joana Paulino ◽  
Myunggi Yi ◽  
Ivan Hung ◽  
Zhehong Gan ◽  
Xiaoling Wang ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Nmr Spectroscopy ◽  
Lipid Bilayers ◽  
Density Functional ◽  
Liquid Crystalline ◽  
Density Functional Theory Calculations ◽  
Bulk Water ◽  
Simple Explanation ◽  
Dynamics Simulations ◽  
Water Hydrogen

Water wires are critical for the functioning of many membrane proteins, as in channels that conduct water, protons, and other ions. Here, in liquid crystalline lipid bilayers under symmetric environmental conditions, the selective hydrogen bonding interactions between eight waters comprising a water wire and a subset of 26 carbonyl oxygens lining the antiparallel dimeric gramicidin A channel are characterized by17O NMR spectroscopy at 35.2 T (or 1,500 MHz for1H) and computational studies. While backbone15N spectra clearly indicate structural symmetry between the two subunits, single site17O labels of the pore-lining carbonyls report two resonances, implying a break in dimer symmetry caused by the selective interactions with the water wire. The17O shifts document selective water hydrogen bonding with carbonyl oxygens that are stable on the millisecond timescale. Such interactions are supported by density functional theory calculations on snapshots taken from molecular dynamics simulations. Water hydrogen bonding in the pore is restricted to just three simultaneous interactions, unlike bulk water environs. The stability of the water wire orientation and its electric dipole leads to opposite charge-dipole interactions for K+ions bound at the two ends of the pore, thereby providing a simple explanation for an ∼20-fold difference in K+affinity between two binding sites that are ∼24 Å apart. The17O NMR spectroscopy reported here represents a breakthrough in high field NMR technology that will have applications throughout molecular biophysics, because of the acute sensitivity of the17O nucleus to its chemical environment.

scholarly journals Origin of hydrophobicity and enhanced water hydrogen bond strength near purely hydrophobic solutes

2016 ◽  
Vol 114 (2) ◽  
pp. 322-327 ◽  
Author(s):  
Joze Grdadolnik ◽  
Franci Merzel ◽  
Franc Avbelj
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Hydrophobic Hydration ◽  
Bulk Water ◽  
Water Molecules ◽  
Classical View ◽  
Fundamental Level ◽  
Hydrophobic Solute ◽  
Hydrophobic Solutes ◽  
Water Hydrogen

Hydrophobicity plays an important role in numerous physicochemical processes from the process of dissolution in water to protein folding, but its origin at the fundamental level is still unclear. The classical view of hydrophobic hydration is that, in the presence of a hydrophobic solute, water forms transient microscopic “icebergs” arising from strengthened water hydrogen bonding, but there is no experimental evidence for enhanced hydrogen bonding and/or icebergs in such solutions. Here, we have used the redshifts and line shapes of the isotopically decoupled IR oxygen–deuterium (O-D) stretching mode of HDO water near small purely hydrophobic solutes (methane, ethane, krypton, and xenon) to study hydrophobicity at the most fundamental level. We present unequivocal and model-free experimental proof for the presence of strengthened water hydrogen bonds near four hydrophobic solutes, matching those in ice and clathrates. The water molecules involved in the enhanced hydrogen bonds display extensive structural ordering resembling that in clathrates. The number of ice-like hydrogen bonds is 10–15 per methane molecule. Ab initio molecular dynamics simulations have confirmed that water molecules in the vicinity of methane form stronger, more numerous, and more tetrahedrally oriented hydrogen bonds than those in bulk water and that their mobility is restricted. We show the absence of intercalating water molecules that cause the electrostatic screening (shielding) of hydrogen bonds in bulk water as the critical element for the enhanced hydrogen bonding around a hydrophobic solute. Our results confirm the classical view of hydrophobic hydration.

scholarly journals Unusual Properties of Water

2012 ◽  
Vol 7 (1) ◽  
pp. 20-23
Author(s):  
Janusz Lipkowski
Keyword(s):  
Hydrogen Bonding ◽  
Cold Water ◽  
Hot Water ◽  
Water Molecules ◽  
Condensed Phases ◽  
Cohesion Energy ◽  
Web Page ◽  
Structures And Properties ◽  
Structural Aspects ◽  
Water Hydrogen

Water has been known for its unusual properties from antiquity when, e.g. was found that hot water freezes faster than cold water. Presently, on the web page 'water' Martin Chaplin [1] lists sixty seven properties of water which may be considered 'anomalous' when comparing to 'normal' chemical substances. Much of this can be attributed to the spatial structure of hydrogen bonding in condensed phases of water. Hydrogen bonding constitutes about 2/3 of cohesion energy of water. However, the remaining 1/3 is definitely not negligible. Combination of the two leads to properties of water in the systems where it plays a role. The very comprehensive range of such systems and common presence of water make the enormous variety of structures and properties of water-containing compounds. In the present paper the non-hydrophilic component of properties of water will be emphasized in combination with the structural aspects of supramolecular bonding of water molecules.

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