The reactions of ground state Cu<sup>+</sup> and Fe<sup>+</sup> with the 20 common amino acids

Lei, Q. Paula; Amster, I. Jonathan

doi:10.1016/1044-0305(96)80518-6

Cited by 63 publications

(43 citation statements)

References 89 publications

(93 reference statements)

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“…The Y 3 ion is also present in greater relative abundance than the y 3 ion. The Y 3 product may be the result of direct cleavage of the amide bonds without oxazolone ring formation and proton transfer as described by Paizs and Suhai [40] ϩ ( Figure S4A), both of which yield predominantly C-terminal sequence ions of types x i , y i , and z i and product ions formed by side-chain cleavage, i.e., v i and w ia , owing to the high proton affinity of the C-terminal arginine [30,41]. Conversely, the photofragment ion spectrum of Lys 1 -BK [M ϩ Cu] ϩ contains nearly equal abundances of N-and C-terminal fragment ions, because the Cu ϩ ion affinities for N-terminal lysine and C-terminal arginine are similar (120.4 kcal mol Ϫ1 and 136.1 kcal mol Ϫ1 , respectively) [30].…”

Section: H]mentioning

confidence: 99%

Comparative studies of 193-nm photodissociation and TOF-TOFMS analysis of bradykinin analogues: The effects of charge site(s) and fragmentation timescales

Morgan

Russell

2006

J. Am. Soc. Mass Spectrom.

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The dissociation reactions of [M ϩ H] ϩ , [M ϩ Na] ϩ , and [M ϩ Cu] ϩ ions of bradykinin (amino acid sequence RPPGFSPFR) and three bradykinin analogues (RPPGF, RPPGFSPF, PPGF-SPFR) are examined by using 193-nm photodissociation and post-source decay (PSD) TOF-TOF-MS techniques. The photodissociation apparatus is equipped with a biased activation cell, which allows us to detect fragment ions that are formed by dissociation of short-lived (Ͻ1 s) photo-excited ions. In our previously reported photodissociation studies, the fragment ions were formed from ions dissociating with lifetimes that exceeded 10 s; thus these earlier photofragment ion spectra and post-source decay (PSD) spectra [composite of both metastable ion (MI) and collision-induced dissociation (CID)] were quite similar. On the other hand, short-lived photo-excited ions dissociate by simple bond cleavage reactions and other high-energy dissociation channels. We also show that product ion types and abundances vary with the location of the charge on the peptide ion. For example, H ϩ and Na ϩ cations can bind to multiple polar functional groups (basic amino acid side chains) of the peptide, whereas Cu ϩ ions preferentially bind to the guanidino group of the arginine side-chain and the N-terminal amine group. Furthermore, when Cu ϩ is the charge carrier, the abundances of non-sequence informative ions, especially loss of small neutral molecules (H 2 O and NH 3 ) is decreased for both photofragment ion and PSD spectra relative to that observed for [ [3] have revolutionized the analysis of biomolecules by mass spectrometry (MS) techniques. Identification of proteins by using "bottom-up" MS techniques, i.e., enzymatic digestion of proteins or protein mixtures followed by peptide mass fingerprinting and database searching [4,5], is now routine, and de novo sequencing [6] and determination of post-translational modifications using tandem mass spectrometry techniques is now commonly practiced in many laboratories. The major factor that complicates peptide structure determination is that the types of fragment ions observed in a tandem mass spectrum are related to the intrinsic properties of the gas-phase peptide ion [7], the activation method used, and the timeframe for probing unimolecular dissociation products [8,9]. For example, utilizing only the internal energy acquired during desorption/ionization and a relatively long fragmentation timescale [ϳ10 s, as in post-source decay (PSD) experiments] favors product ions formed via the lowest energy channels [10], i.e., b i -and y i -type fragments [11,12]. As we showed previously, the observed fragment ions and their relative abundances change significantly if the timescale of the experiment is altered [13].Collisional activation of gas-phase peptide ions with a neutral gas (eV to several keV collision energies) can be employed to increase the internal energy of the ions and, thereby, enhance the abundances of sequence informative fragment ions; however, the resulting spectra also contain large numbers of non-se...

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Section: H]mentioning

confidence: 99%

Comparative studies of 193-nm photodissociation and TOF-TOFMS analysis of bradykinin analogues: The effects of charge site(s) and fragmentation timescales

Morgan

Russell

2006

J. Am. Soc. Mass Spectrom.

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“…The traditional method is to mix a copper salt solution with the sample or by direct production of cations from metallic copper. For example, Cu ϩ ions have been generated in the gas phase by direct ionization of the metal in fast atom bombardment and in MALDI [15][16][17]. In aqueous solutions, Cu ϩ is unstable, and specific sample preparations are required (anaerobic conditions, adequate solvent).…”

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confidence: 99%

On-line electrogeneration of copper-peptide complexes in microspray mass spectrometry

Prudent

2008

J. Am. Soc. Mass Spectrom.

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“…Metal ions are also possibly inserting into bonds along the peptide backbone, producing a‐ or b‐ions or both. Gas‐phase ion chemistry studies have established that singly charged metal ions often insert into C–C and C–N bonds, and doubly or triply charged metal ions should be even more reactive due to their greater electron deficiency.…”

Section: Resultsmentioning

confidence: 99%

Effects of transition metal ion coordination on the collision‐induced dissociation of polyalanines

2011

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Transition metal-polyalanine complexes were analyzed in a high-capacity quadrupole ion trap after electrospray ionization. Polyalanines have no polar amino acid side chains to coordinate metal ions, thus allowing the effects metal ion interaction with the peptide backbone to be explored. Positive mode mass spectra produced from peptides mixed with salts of the first row transition metals Cr(III), Fe(II), Fe(III), Co(II), Ni(II), Cu(I), and Cu(II) yield singly and doubly charged metallated ions. These precursor ions undergo collision-induced dissociation (CID) to give almost exclusively metallated N-terminal product ions whose types and relative abundances depend on the identity of the transition metal. For example, Cr(III)-cationized peptides yield CID spectra that are complex and have several neutral losses, whereas Fe(III)-cationized peptides dissociate to give intense non-metallated products. The addition of Cu(II) shows the most promise for sequencing. Spectra obtained from the CID of singly and doubly charged Cu-heptaalanine ions, [M + Cu - H](+) and [M + Cu](2+) , are complimentary and together provide cleavage at every residue and no neutral losses. (This contrasts with [M + H](+) of heptaalanine, where CID does not provide backbone ions to sequence the first three residues.) Transition metal cationization produces abundant metallated a-ions by CID, unlike protonated peptides that produce primarily b- and y-ions. The prominence of metallated a-ions is interesting because they do not always form from b-ions. Tandem mass spectrometry on metallated (Met = metal) a- and b-ions indicate that [b(n) + Met - H](2+) lose CO to form [a(n) + Met - H](2+), mimicking protonated structures. In contrast, [a(n) + Met - H](2+) eliminate an amino acid residue to form [a(n-1) + Met - H](2+), which may be useful in sequencing.

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The reactions of ground state Cu⁺ and Fe⁺ with the 20 common amino acids

Cited by 63 publications

References 89 publications

Comparative studies of 193-nm photodissociation and TOF-TOFMS analysis of bradykinin analogues: The effects of charge site(s) and fragmentation timescales

Comparative studies of 193-nm photodissociation and TOF-TOFMS analysis of bradykinin analogues: The effects of charge site(s) and fragmentation timescales

On-line electrogeneration of copper-peptide complexes in microspray mass spectrometry

Effects of transition metal ion coordination on the collision‐induced dissociation of polyalanines

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The reactions of ground state Cu+ and Fe+ with the 20 common amino acids

Cited by 63 publications

References 89 publications

Comparative studies of 193-nm photodissociation and TOF-TOFMS analysis of bradykinin analogues: The effects of charge site(s) and fragmentation timescales

Comparative studies of 193-nm photodissociation and TOF-TOFMS analysis of bradykinin analogues: The effects of charge site(s) and fragmentation timescales

On-line electrogeneration of copper-peptide complexes in microspray mass spectrometry

Effects of transition metal ion coordination on the collision‐induced dissociation of polyalanines

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The reactions of ground state Cu⁺ and Fe⁺ with the 20 common amino acids