The carbon-nitrogenpeptidebond is rigid The electric dipole of peptide bonds generates a net dipole, a fundamental property that influences protein structure and function. This inherent polarity arises from the unequal sharing of electrons within the peptide bond itself, primarily due to the electronegativity differences between oxygen, carbon, and nitrogen atoms. Understanding this phenomenon is crucial for comprehending how proteins fold, interact, and carry out their biological roles.
A peptide bond, formed between two amino acids through a dehydration reaction, consists of a carbonyl group (C=O) and an amino group (N-H)- peptide bond of residue n is hydrogen bonded to to residue n+4 -electric dipole of peptide bonds generates a net dipole- backbone NH groups are H-bonded .... The oxygen atom in the carbonyl group is highly electronegative, pulling electron density away from the carbon atom作者：WH Koppenol·1991·被引用次数：65—Vertebrate cytochromes c andthecytochromes c of insects and plants have, on average,dipolemoments of 320 and 340 debye, respectively.. Similarly, the nitrogen atom in the amino group is less electronegative than the hydrogen atoms attached to it. This charge separation creates a permanent dipole moment within each peptide bond, with a partial negative charge on the oxygen and a partial positive charge on the nitrogen and associated hydrogen.
While a single peptide bond possesses a dipole moment, the overall dipole of a polypeptide chain is a result of the collective orientation of these individual bond dipoles. In many protein structures, particularly the alpha-helix, these peptide bonds align in a specific, parallel fashion.Dipole Cooperativity and Polarization Frustration Determine ... This alignment leads to a cumulative effect, creating a significant macroscopic dipole moment that spans across multiple amino acid residues and runs along the axis of the helix. This organized arrangement is a key factor in the stability and electrostatic properties of these secondary structures.
The alpha-helix is a common protein secondary structure characterized by a right-handed helical arrangement of amino acids. Within an alpha-helix, each peptide bond's dipole moment is oriented in a similar direction, pointing generally towards the C-terminus of the polypeptide chain.作者：JA Lemkul·2015·被引用次数：32—Inthepresent study,theenhanced unfolding is shown to be due tothemutated side chains alteringthelocalpeptide-bond dipolemoments leading to local ... This consistent orientation results in a substantial net dipole moment for the entire helix.Dipole Cooperativity and Polarization Frustration Determine ... This "helix dipole" can influence protein folding, binding interactions, and even the behavior of charged molecules in the protein's vicinity.Biochemistry,530:,, Introduc5on,to,Structural,Biology, The strength of this macroscopic dipole is influenced by the length of the helix and the specific amino acid sequence, with certain residues potentially affecting the local charge distributionDipole-induced self-assembly of helical β-peptides.
Beta-sheets, another prevalent protein secondary structure, are formed by hydrogen bonds between adjacent polypeptide strands. While the peptide bonds within a beta-strand also have individual dipole moments, their arrangement in a sheet structure leads to a different overall dipole characteristic compared to alpha-helicesThis transientdipolehas an associatedelectricfield that polarizes any nearby non polar atom, producing a transientdipolein it.Theinteraction betweenthe.... In beta-pleated sheets, the peptide bonds are oriented in a more zigzag or pleated manner作者：D Sengupta·2005·被引用次数：127—Asthe peptidelength increases,theterminal screened andtheextent ofthescreening depends only onthepolarity ofthesolvent. charges .... The carbonyl oxygen of one peptide bond is hydrogen-bonded to the amide hydrogen of a neighboring strand. This arrangement results in a net dipole moment across the sheet, though it's typically less pronounced and more distributed than the strong axial dipole of an alpha-helix.- peptide bond of residue n is hydrogen bonded to to residue n+4 -electric dipole of peptide bonds generates a net dipole- backbone NH groups are H-bonded ... The polarity of the amino and carbonyl groups still contributes to the overall electrostatic landscape of the proteinUse the information gathered in the Protein.
The net dipole generated by peptide bonds has significant functional implications in proteinsdipole-induced-effects-on-charge-transfer-and- ....
* Protein Folding and Stability: The electrostatic interactions arising from these dipoles can contribute to the forces that drive protein folding and stabilize various secondary and tertiary structures. The helix dipole, for instance, can interact with charged residues or external molecules.
* Binding Interactions: The polarized nature of peptide bonds and the resulting macroscopic dipoles can play a role in the specific binding of ligands, ions, or other macromolecules to proteins.This transientdipolehas an associatedelectricfield that polarizes any nearby non polar atom, producing a transientdipolein it.Theinteraction betweenthe... These electrostatic forces can guide molecular recognition events.
* Enzyme Activity: In some cases, the electric field created by these dipoles can influence the catalytic activity of enzymes by affecting the transition states of reactions or stabilizing charged intermediatesAlpha Helix Hydrogen Bonding: Videos & Practice Problems.
* Membrane Interactions: For proteins embedded in or interacting with cell membranes, the dipole moments can influence their orientation and integration within the lipid bilayer.Computation of the dipole moment of protein molecules ...
Several factors can influence the dipole moment of peptide bonds and the overall protein structure:
* Amino Acid Sequence: The specific sequence of amino acids can affect the local polarity and the degree of alignment of peptide bond dipoles.
* Secondary Structure: As discussed, the arrangement of peptide bonds in alpha-helices and beta-sheets leads to distinct dipole characteristics.
* Post-Translational Modifications: Modifications to amino acid residues can alter their charge and polarity, thereby influencing the overall dipole moment.- peptide bond of residue n is hydrogen bonded to to residue n+4 -electric dipole of peptide bonds generates a net dipole- backbone NH groups are H-bonded ...
* Solvent Environment: The polarity of the surrounding solvent can screen or enhance electrostatic interactions, affecting the effective dipole moment.
In summary, the electric dipole of peptide bonds is a fundamental molecular feature that, through collective alignment, generates net dipole moments in protein structures like alpha-helices and beta-sheets.作者：CA Miller·2008·被引用次数：31—In this work,theinteractions between β -peptidesare investigated for helix-formingpeptidesusing molecular simulation. These dipoles are critical for protein folding, stability, and a wide range of biological functionsInduced Dipole–Dipole Interactions Influence the Unfolding ....
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