| 词汇 | example_english_hydrogen-bond |
| 释义 | Examples of hydrogen bondThese examples are from corpora and from sources on the web. Any opinions in the examples do not represent the opinion of the Cambridge Dictionary editors or of Cambridge University Press or its licensors. One of the aspartates that formerly interacted with the tyrosine now forms a hydrogenbond with a conserved histidine. None of the sulfide ions make any favorable hydrogenbond to the protein. Its frequency depends on the strength of the hydrogenbond. The reason for this is easily understood since ammonia forms a hydrogenbond that imidazole (or histidine) cannot form. Furthermore, simulated annealing does not provide well-defined conformations, but the different conformations that are observed are consistent with several possible hydrogenbond combinations. The transition is opposed by the loss in conformational entropy, and driven by gains in free energy due to hydrophobic burial and hydrogenbond formation. The environment of the iron-sulfur cluster is not exceptional having, on average, one hydrogenbond per liganding cysteine and otherwise a surrounding hydrophobic environment. Note the hydrogenbond between the exocyclic amine of the 3h cytosine base and the non-bridging oxygen of the phosphate at the exchange point. Unlike the alcohols, general anaesthetics cannot hydrogenbond to phospholipid headgroups. The second condition ensures that the hydrogenbond is more or less linear. The second distance restraint restricts the angle of the hydrogenbond. To represent the key feature of a polar solvent like water, the capability of hydrogenbond formation has to be represented. Formally, the hydrogenbond has to be treated as a combination of a dipole-dipole interaction and a charge transfer reaction. The relation should be particularly useful in studies of enzyme catalytic sites or other protein-ligand interactions in which hydrogenbond strength may play a key role. Correlation with hydrogenbond length. Hydrogenbond acceptors, mostly nitrogen but also oxygen, reside in the ring system of the inhibitors. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The hydrogenbond between the enzyme and the phosphate group of the substrate makes such decomposition stereoelectronically unfavorable. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Hydrogen bonds form between chains, and side chains form above and below the plane of the hydrogenbond network. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. During the course of the reaction, one fragment develops partial negative character and the transition state can be stabilized by accepting hydrogenbond(s). From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. At this point, reaction discovery is useful, but more detailed mechanistic study is required to realize the full potential of hydrogenbond catalysis. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. However, there are several challenges that must be overcome before hydrogenbond catalysis can achieve its full potential in terms of synthetic utility. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. However, contemporary hydrogenbond catalysis is primarily focused on a few types of systems that experimentally seem to be effective in a variety of situations. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. In the field hydrogenbond catalysis, chemists have not yet reached a stage where new types of reactivity can be easily and systematically targeted. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. These are some of the earliest hydrogenbond catalysts investigated. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Therefore, the formally negative oxygen engages in a much stronger hydrogenbond than the starting carbonyl oxygen because of its increased negative charge. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Rotary evaporation for high boiling hydrogenbond-forming solvents such as water is often a last recourse, as other evaporation methods or freeze-drying (lyophilization) are available. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. A hydrogenbond results when this strong positive charge density attracts a lone pair of electrons on another heteroatom, which becomes the hydrogen-bond "acceptor". From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. His books on crystal engineering (1989) and on the weak hydrogenbond in structural chemistry and biology (1999) are especially notable. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. In protic solvents, the equilibrium lies towards the keto form as the intramolecular hydrogenbond competes with hydrogen bonds originating from the solvent. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Molecular ions that contain at least one carbon to hydrogenbond are called "organic ions". From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Historically, the most favored model has been the hydrogenbond switching model. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Its role can be thought as capping the hydrogenbond interactions that would otherwise be satisfied by the polypeptide backbone. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. However, perfluoric peracids are still able to hydrogenbond with protected alcohols and give normal selectivity with the hydrogen present on the peracid. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Solubility in water can be estimated from the number of hydrogenbond donors vs. alkyl sidechains in the molecule. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. An expanded schematic reveals the underlying chemistry of the problem: the potential for hydrogenbond formation between unrelated base pairs. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Appropriate geometrical correspondence of hydrogenbond donors and acceptors allows only the right pairs to form stably. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. An electronegative atom such as fluorine, oxygen, or nitrogen is a hydrogenbond acceptor, whether it is bonded to a hydrogen atom or not. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The subscripts refer to the number of atoms (including the hydrogen) in the closed loop formed by the hydrogenbond. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. This disrupts the hydrogenbond network and disorders the conformation of two phosphorylation loops. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. For example the carbon to hydrogenbond in methane is different from that in methyl chloride. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. This single hydrogenbond is then removed to create the tertiary hairpin; a five-residue loop with doubly bound residues. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. O and other weak interactions have a hydrogenbond character. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The sulfonyl group serves as a hydrogenbond acceptor. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The hydrogenbond is not without its critics. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The single mutation, in this case changing a substituent on an aromatic ring, results in secondary effects such as a change in hydrogenbond strength. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. An example of a hydrogenbond acceptor that "does not" have a hydrogen atom bonded to it, is the oxygen atom in diethyl ether. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The hydrogenbond is often described as an electrostatic dipole-dipole interaction. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. As a scientist, a physicist, he achieved a worldwide reputation for hydrogenbond research. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. When base pairing with adenine, uracil acts as both a hydrogenbond acceptor and a hydrogenbond donor. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Together with his students he demonstrated the existence and wide-ranging importance of the hydrogenbond. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Depsipeptides have also been used in research to probe the importance of hydrogenbond networks in protein folding kinetics and thermodynamics. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. It can also form the same hydrogenbond with an adenine base paired to a thymine. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The typical length of a hydrogenbond in water is 197 pm. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. In the crystal, the rings of each molecule are co-planar and the amine units connect molecules to form an intermolecular 3-dimensional hydrogenbond network. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The phenolic hydroxyl of tyrosine forms a hydrogenbond with the terminal carboxylate of the ligand. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. One hydrogenbond is then removed to create a three-residue loop, which is the secondary hairpin of class 1. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Single amino acid replacements may destroy a particular hydrogenbond, but will not unfold the hairpin or change its class. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Both are strong hydrogenbond acceptors, and their oxygen atoms bind metal cations. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The hydrogenbond is often described as a strong electrostatic dipole-dipole interaction. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The compound exhibits intra- and intermolecular hydrogenbond involving the neighbouring amine and hydroxyl groups. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. N atoms across a hydrogenbond, indicates the presence or absence of basepairing. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. It is result of formation of intra-molecular hydrogenbond, which is conjugated with phenyl rings. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. In this structure there is a hydrogenbond between the hydroxyl group and the adjacent pyridine ring. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. They participate in hydrogen bonds as hydrogen-bond acceptors, but can not act as hydrogen-bond donors, unlike their parent alcohols. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The molecule should have an oxygen atom, preferably an ester-like oxygen capable of participating in a hydrogenbond. 4. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Sens interacts with the substrate to yield a radical substrate, usually through the homolytic bond breaking of a hydrogenbond on the substrate. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Both the alpha helix and the beta sheet represent a way of saturating all the hydrogenbond donors and acceptors in the peptide backbone. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. In contrast, we lack a general, systematic mechanistic understanding of the steps of hydrogenbond catalysis and how to influence them. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Nevertheless, strong acid catalysts are often grouped with hydrogenbond catalysts as they represent on extreme on this continuum and their catalytic behaviors share similarities. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. A protein backbone hydrogenbond incompletely shielded from water attack is a dehydron. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The ideal bond angle depends on the nature of the hydrogenbond donor. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. This type of bond is much stronger than a normal hydrogenbond. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. In the published examples, hydrogenbond catalysis is mainly used in the beginning stages to quickly access early intermediates with high enantiomeric enrichment. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Catalytic amounts of hydrogenbond donors can promote reactions through a variety of different mechanisms. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. In addition, a second hydrogenbond is formed between the tyrosine and a peptide linkage of longer peptide substrates. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. Furthermore, the dehydration stabilizes the hydrogenbond by destabilizing the nonbonded state consisting of dehydrated isolated charges. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. The hydrogenbond limits the resonance of the aromatic ring so the absorbance of the sample is limited as well. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. However, vanadium complexes do not hydrogenbond with their substrates. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. It has been shown that a dihedral angle of 120 best directs substrates which hydrogenbond with the directing group. From Wikipedia This example is from Wikipedia and may be reused under a CC BY-SA license. These examples are from corpora and from sources on the web. Any opinions in the examples do not represent the opinion of the Cambridge Dictionary editors or of Cambridge University Press or its licensors. |
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