Dataset Information

Tautomerization of H⁺KPGG: Entropic Consequences of Strong Hydrogen-Bond Networks in Peptides.

ABSTRACT: Ion mobility spectrometry-mass spectrometry and quantum chemical calculations are used to determine the structures and stabilities of the singly protonated peptide H⁺KPGG. The two peaks making up the IMS distribution are shown to be tautomers differing by the location of the extra proton on either the lysine side chain or the N-terminus. The lysine-protonated tautomer is strongly preferred entropically while being disfavored in terms of the electronic energy and enthalpy. This relationship is shown, through comparison of all low-lying conformers of both tautomers, to be related to the strong hydrogen-bond network of the N-terminally protonated tautomer. A general relationship is demonstrated wherein stronger cross-peptide hydrogen-bond networks result in entropically disfavored conformers. Further effects of the H⁺KPGG hydrogen-bond network are probed by computationally examining singly and doubly methylated analogues. These results demonstrate the importance of the entropic consequences of hydrogen bonds to peptide stability as well as techniques for perturbing the hydrogen-bond network and folding preferences of peptides via minimal chemical modification.

SUBMITTER: Beckett D

PROVIDER: S-EPMC10405267 | biostudies-literature | 2023 Aug

REPOSITORIES: biostudies-literature

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Tautomerization of H<sup>+</sup>KPGG: Entropic Consequences of Strong Hydrogen-Bond Networks in Peptides.

Beckett Daniel D El-Baba Tarick J TJ Zhang Zhichao Z Clemmer David E DE Raghavachari Krishnan K

The journal of physical chemistry. A 20230725 30

Ion mobility spectrometry-mass spectrometry and quantum chemical calculations are used to determine the structures and stabilities of the singly protonated peptide H<sup>+</sup>KPGG. The two peaks making up the IMS distribution are shown to be tautomers differing by the location of the extra proton on either the lysine side chain or the N-terminus. The lysine-protonated tautomer is strongly preferred entropically while being disfavored in terms of the electronic energy and enthalpy. This relatio ...[more]

PMID: 37490716

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Project description:Hydrogen-bonding networks in proteins considered as structural tensile elements are in balance separately from any other stabilising interactions that may be in operation. The hydrogen bond arrangement in the network is reminiscent of tensegrity structures in architecture and sculpture. Tensegrity has been discussed before in cells and tissues and in proteins. In contrast to previous work only hydrogen bonds are studied here. The other interactions within proteins are either much stronger - covalent bonds connecting the atoms in the molecular skeleton or weaker forces like the so-called hydrophobic interactions. It has been demonstrated that the latter operate independently from hydrogen bonds. Each category of interaction must, if the protein is to have a stable structure, balance out. The hypothesis here is that the entire hydrogen bond network is in balance without any compensating contributions from other types of interaction. For sidechain-sidechain, sidechain-backbone and backbone-backbone hydrogen bonds in proteins, tensegrity balance ("closure") is required over the entire length of the polypeptide chain that defines individually folding units in globular proteins ("domains") as well as within the repeating elements in fibrous proteins that consist of extended chain structures. There is no closure to be found in extended structures that do not have repeating elements. This suggests an explanation as to why globular domains, as well as the repeat units in fibrous proteins, have to have a defined number of residues. Apart from networks of sidechain-sidechain hydrogen bonds there are certain key points at which this closure is achieved in the sidechain-backbone hydrogen bonds and these are associated with demarcation points at the start or end of stretches of secondary structure. Together, these three categories of hydrogen bond achieve the closure that is necessary for the stability of globular protein domains as well as repeating elements in fibrous proteins.

Dataset Information

Tautomerization of H⁺KPGG: Entropic Consequences of Strong Hydrogen-Bond Networks in Peptides.

Publications

Tautomerization of H<sup>+</sup>KPGG: Entropic Consequences of Strong Hydrogen-Bond Networks in Peptides.

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Dataset Information

Tautomerization of H+KPGG: Entropic Consequences of Strong Hydrogen-Bond Networks in Peptides.

Publications

Tautomerization of H<sup>+</sup>KPGG: Entropic Consequences of Strong Hydrogen-Bond Networks in Peptides.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets

Tautomerization of H⁺KPGG: Entropic Consequences of Strong Hydrogen-Bond Networks in Peptides.