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In nylon, hydrogen bonds between carbonyl and the amide NH effectively link adjacent chains, which gives the material mechanical strength. Hydrogen bonds also affect the aramid fibre, where hydrogen bonds stabilize the linear chains laterally. The chain axes are aligned along the fibre axis, making the fibres extremely stiff and strong.
Most importantly, the N-H group of an amino acid forms a hydrogen bond with the C=O group of the amino acid five residues earlier; this repeated i + 5 → i hydrogen bonding defines a π-helix. Similar structures include the 3 10 helix (i + 3 → i hydrogen bonding) and the α-helix (i + 4 → i hydrogen bonding). Top view of the same helix ...
[17]: 39 Most importantly, the N-H group of an amino acid forms a hydrogen bond with the C=O group of the amino acid three residues earlier; this repeated i + 3 → i hydrogen bonding defines a 3 10-helix. Similar structures include the α-helix (i + 4 → i hydrogen bonding) and the π-helix i + 5 → i hydrogen bonding. [17]: 44–45 [19]
Hydrogen bond: A hydrogen bond is a specific type of dipole-dipole interaction between a partially positive hydrogen atom and a partially negative electron donor that contain a pair of electrons such as oxygen, fluorine and nitrogen. The strength of hydrogen bond depends on the chemical nature and geometric arrangement of each group.
Preliminary binding of a ligand near to the entrance breaks hydrogen bonds S212-E474, S207-H172 in the open form of CYP2B4 and hydrogen bonds E218-A102, Q215-L51 are formed that fix the entrance in the closed form as the HB plot reveals. The second step is the transfer of the first electron from NADPH via an electron transfer chain. For the ...
Hydrogen bonds contribute to the stability of ion pairs with e.g. protonated ammonium ions, and with anions is formed by deprotonation as in the case of carboxylate, phosphate etc; then the association constants depend on the pH. Entropic driving forces for ion pairing (in absence of significant H-bonding contributions) are also found in ...
Get ready for all of today's NYT 'Connections’ hints and answers for #550 on Thursday, December 12, 2024. Today's NYT Connections puzzle for Thursday, December 12, 2024The New York Times.
Between A and T there are two hydrogen bonds, while there are three between C and G. Right: two complementary strands of DNA. Complementarity is achieved by distinct interactions between nucleobases: adenine, thymine (uracil in RNA), guanine and cytosine. Adenine and guanine are purines, while thymine, cytosine and uracil are pyrimidines ...