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Electron capture

About: Electron capture is a research topic. Over the lifetime, 7401 publications have been published within this topic receiving 117018 citations. The topic is also known as: K-electron capture & K-capture.


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Journal ArticleDOI
TL;DR: For proteins of < 20 kDa, this new radical site dissociation method cleaves different and many more backbone bonds than the conventional MS/MS methods that add energy directly to the even-electron ions.
Abstract: For proteins of <20 kDa, this new radical site dissociation method cleaves different and many more backbone bonds than the conventional MS/MS methods (e.g., collisionally activated dissociation, CAD) that add energy directly to the even-electron ions. A minimum kinetic energy difference between the electron and ion maximizes capture; a 1 eV difference reduces capture by 103. Thus, in an FTMS ion cell with added electron trapping electrodes, capture appears to be achieved best at the boundary between the potential wells that trap the electrons and ions, now providing 80 ± 15% precursor ion conversion efficiency. Capture cross section is dependent on the ionic charge squared (z2), minimizing the secondary dissociation of lower charge fragment ions. Electron capture is postulated to occur initially at a protonated site to release an energetic (∼6 eV) H• atom that is captured at a high-affinity site such as −S−S− or backbone amide to cause nonergodic (before energy randomization) dissociation. Cleavages betwe...

952 citations

Journal ArticleDOI
TL;DR: In this paper, the authors discuss the role of electron scattering and nuclear structure in the development of the first-order particle beamforming and nuclear nuclear nuclear structures, and propose a method for their analysis.
Abstract: (1966). Electron scattering and nuclear structure. Advances in Physics: Vol. 15, No. 57, pp. 1-109.

669 citations

Journal ArticleDOI
TL;DR: RRKM calculations indicate that H• capture Dissociation of backbone bonds in multiply-charged proteins represents nonergodic behavior, as proposed for the original direct mechanism of electron capture dissociation.
Abstract: Disulfide bonds in gaseous multiply-protonated proteins are preferentially cleaved in the mass spectrometer by low-energy electrons, in sharp contrast to excitation of the ions by photons or low-energy collisions. For S−S cyclized proteins, capture of one electron can break both an S−S bond and a backbone bond in the same ring, or even both disulfide bonds holding two peptide chains together (e.g., insulin), enhancing the sequence information obtainable by tandem mass spectrometry on proteins in trace amounts. Electron capture at uncharged S−S is unlikely; cleavage appears to be due to the high S−S affinity for H• atoms, consistent with a similar favorability found for tryptophan residues. RRKM calculations indicate that H• capture dissociation of backbone bonds in multiply-charged proteins represents nonergodic behavior, as proposed for the original direct mechanism of electron capture dissociation.

538 citations

Journal ArticleDOI
TL;DR: In this paper, the electron capture, positron capture and beta-decay rates for more than 100 nuclei in the mass range A=45 −65 were determined based on large-scale shell-model calculations.

523 citations

Journal ArticleDOI
TL;DR: By comparing the results from different experiments and theory, it is possible to determine fundamental mechanisms that are involved in the dissociation of the biomolecules and the production of single- and double-strand breaks in DNA.
Abstract: The damage induced by the impact of low energy electrons (LEE) on biomolecules is reviewed from a radiobiological perspective with emphasis on transient anion formation. The major type of experiments, which measure the yields of fragments produced as a function of incident electron energy (0.1-30 eV), are briefly described. Theoretical advances are also summarized. Several examples are presented from the results of recent experiments performed in the gas-phase and on biomolecular films bombarded with LEE under ultra-high vacuum conditions. These include the results obtained from DNA films and those obtained from the fragmentation of elementary components of the DNA molecule (i.e., the bases, sugar and phosphate group analogs and oligonucleotides) and of proteins (e.g. amino acids). By comparing the results from different experiments and theory, it is possible to determine fundamental mechanisms that are involved in the dissociation of the biomolecules and the production of single- and double-strand breaks in DNA. Below 15 eV, electron resonances (i.e., the formation of transient anions) play a dominant role in the fragmentation of all biomolecules investigated. These transient anions fragment molecules by decaying into dissociative electronically excited states or by dissociating into a stable anion and a neutral radical. These fragments can initiate further reactions within large biomolecules or with nearby molecules and thus cause more complex chemical damage. Dissociation of a transient anion within DNA may occur by direct electron attachment at the location of dissociation or by electron transfer from another subunit. Damage to DNA is dependent on the molecular environment, topology, type of counter ion, sequence context and chemical modifications.

481 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202333
202274
202155
202097
201995
201875