scholarly journals Physicochemical Determinants of Passive Membrane Permeability:  Role of Solute Hydrogen-Bonding Potential and Volume.

2002 ◽  
Vol 45 (10) ◽  
pp. 2122-2122 ◽  
Author(s):  
Jay T. Goodwin ◽  
Robert A. Conradi ◽  
Norman F. H. Ho ◽  
Philip S. Burton
Keyword(s):  
Hydrogen Bonding ◽  
Membrane Permeability ◽  
Hydrogen Bonding Potential ◽  
Passive Membrane

Physicochemical Determinants of Passive Membrane Permeability:  Role of Solute Hydrogen-Bonding Potential and Volume

2001 ◽  
Vol 44 (22) ◽  
pp. 3721-3729 ◽  
Author(s):  
Jay T. Goodwin ◽  
Robert A. Conradi ◽  
Norman F. H. Ho ◽  
Philip S. Burton
Keyword(s):  
Hydrogen Bonding ◽  
Membrane Permeability ◽  
Hydrogen Bonding Potential ◽  
Passive Membrane

Conformational Flexibility, Internal Hydrogen Bonding, and Passive Membrane Permeability:  Successful in Silico Prediction of the Relative Permeabilities of Cyclic Peptides

2006 ◽  
Vol 128 (43) ◽  
pp. 14073-14080 ◽  
Author(s):  
Taha Rezai ◽  
Jonathan E. Bock ◽  
Mai V. Zhou ◽  
Chakrapani Kalyanaraman ◽  
R. Scott Lokey ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Membrane Permeability ◽  
In Silico ◽  
Cyclic Peptides ◽  
Conformational Flexibility ◽  
In Silico Prediction ◽  
Relative Permeabilities ◽  
Internal Hydrogen ◽  
Passive Membrane

scholarly journals Role of Hoogsteen Edge Hydrogen Bonding at Template Purines in Nucleotide Incorporation by Human DNA Polymerase ι

2006 ◽  
Vol 26 (17) ◽  
pp. 6435-6441 ◽  
Author(s):  
Robert E. Johnson ◽  
Lajos Haracska ◽  
Louise Prakash ◽  
Satya Prakash
Keyword(s):  
Hydrogen Bonding ◽  
Dna Polymerase ◽  
Active Site ◽  
Dna Polymerases ◽  
Human Dna ◽  
Nucleotide Incorporation ◽  
Template Specificity ◽  
Hydrogen Bonding Potential ◽  
Dna Polymerase Ι

ABSTRACT Human DNA polymerase ι (Pol ι) differs from other DNA polymerases in that it exhibits a marked template specificity, being more efficient and accurate opposite template purines than opposite pyrimidines. The crystal structures of Pol ι with template A and incoming dTTP and with template G and incoming dCTP have revealed that in the Pol ι active site, the templating purine adopts a syn conformation and forms a Hoogsteen base pair with the incoming pyrimidine which remains in the anti conformation. By using 2-aminopurine and purine as the templating residues, which retain the normal N7 position but lack the N6 of an A or the O6 of a G, here we provide evidence that whereas hydrogen bonding at N6 is dispensable for the proficient incorporation of a T opposite template A, hydrogen bonding at O6 is a prerequisite for C incorporation opposite template G. To further analyze the contributions of O6 and N7 hydrogen bonding to DNA synthesis by Pol ι, we have examined its proficiency for replicating through the 6 O-methyl guanine and 8-oxoguanine lesions, which affect the O6 and N7 positions of template G, respectively. We conclude from these studies that for proficient T incorporation opposite template A, only the N7 hydrogen bonding is required, but for proficient C incorporation opposite template G, hydrogen bonding at both the N7 and O6 is an imperative. The dispensability of N6 hydrogen bonding for proficient T incorporation opposite template A has important biological implications, as that would endow Pol ι with the ability to replicate through lesions which impair the Watson-Crick hydrogen bonding potential at both the N1 and N6 positions of templating A.

scholarly journals Deciphering the Role of π-Interactions in Polyelectrolyte Complexes Using Rationally Designed Peptides

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2074
Author(s):  
Sara Tabandeh ◽  
Cristina Elisabeth Lemus ◽  
Lorraine Leon
Keyword(s):  
Hydrogen Bonding ◽  
Phase Separation ◽  
Liquid Phase ◽  
Charge Density ◽  
Secondary Structures ◽  
Liquid Phase Separation ◽  
Polyelectrolyte Complexes ◽  
Π Interactions ◽  
Liquid Liquid Phase Separation

Electrostatic interactions, and specifically π-interactions play a significant role in the liquid-liquid phase separation of proteins and formation of membraneless organelles/or biological condensates. Sequence patterning of peptides allows creating protein-like structures and controlling the chemistry and interactions of the mimetic molecules. A library of oppositely charged polypeptides was designed and synthesized to investigate the role of π-interactions on phase separation and secondary structures of polyelectrolyte complexes. Phenylalanine was chosen as the π-containing residue and was used together with lysine or glutamic acid in the design of positively or negatively charged sequences. The effect of charge density and also the substitution of fluorine on the phenylalanine ring, known to disrupt π-interactions, were investigated. Characterization analysis using MALDI-TOF mass spectroscopy, H NMR, and circular dichroism (CD) confirmed the molecular structure and chiral pattern of peptide sequences. Despite an alternating sequence of chirality previously shown to promote liquid-liquid phase separation, complexes appeared as solid precipitates, suggesting strong interactions between the sequence pairs. The secondary structures of sequence pairs showed the formation of hydrogen-bonded structures with a β-sheet signal in FTIR spectroscopy. The presence of fluorine decreased hydrogen bonding due to its inhibitory effect on π-interactions. π-interactions resulted in enhanced stability of complexes against salt, and higher critical salt concentrations for complexes with more π-containing amino acids. Furthermore, UV-vis spectroscopy showed that sequences containing π-interactions and increased charge density encapsulated a small charged molecule with π-bonds with high efficiency. These findings highlight the interplay between ionic, hydrophobic, hydrogen bonding, and π-interactions in polyelectrolyte complex formation and enhance our understanding of phase separation phenomena in protein-like structures.

Mechanisms on the stability and instability of water-in-oil emulsion stabilized by interfacially active asphaltenes: Role of hydrogen bonding reconstructing

Fuel ◽  
2021 ◽  
Vol 297 ◽  
pp. 120763
Author(s):  
Jun Ma ◽  
Yongli Yang ◽  
Xingang Li ◽  
Hong Sui ◽  
Lin He
Keyword(s):  
Hydrogen Bonding ◽  
Oil Emulsion ◽  
Stability And Instability ◽  
The Stability ◽  
Water In Oil Emulsion
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