Infrared multiple photon dissociation spectroscopy of cationized cysteine: Effects of metal cation size on gas-phase conformation

Structural characterization of gas-phase cysteine and cysteine methyl ester complexes with zinc and cadmium dications by infrared multiple photon dissociation spectroscopy

“…In all cases, these CQO stretches occur in a lower frequency range than previously observed for alkali metal cationized Cys, 1718 cm À1 for Li + (Cys) to 1745 cm À1 for Cs + (Cys). 36 Clearly, interaction with the doubly charged metal (or nearly doubly charged for CdCl + ) weakens the CO bond more than the singly charged metal cations. The band at 1580 cm À1 , the NH 2 bend, shifts little in most spectra, but shifts to the blue for CdCl + (CysOMe).…”

Amino Acid Oxidation: A Combined Study of Cysteine Oxo Forms by IRMPD Spectroscopy and Simulations

“…The unambiguous and detailed characterization of the structural and dynamic behavior of these transient intermediates in isolated environments, in which external interferences are absent, will help to reveal intrinsic properties relevant to their biological activity. The inherent bonding and conformational features of cysteine in its (de)protonated, nitrosated, and metal‐tagged forms have been previously interrogated both in the free amino acid and in the residue embodied in the glutathione peptide by a joint computational and experimental infrared multiple photon dissociation (IRMPD) assay. IRMPD spectroscopy, coupled with ESI tandem mass spectrometry (MS/MS), is a pivotal tool to provide direct structural clues about gaseous (bio)molecular ions, including (de)protonation site, metal‐binding patterns, and local intramolecular interactions in both native and modified amino acids and peptides, DNA/RNA bases and nucleotides, cluster ions, and fragmentation products …”

“…[18] Recently,avariety of mass spectrometric studies have been able to identify the reactive intermediates formed by (interfacial) ozonolysis of deprotonated cysteineatthe air-liquid interface, [5,19] to probe the stability and fragmentation behavior of intact and modified sulfinyl radical ions, [20,21] and elucidate the intrinsic mechanism involved in the formationo fc ysteine oxo forms [cysSO x ] À (x = 1, 2, 3) and sulfenate radicala nions in the gas phase. [22] The unambiguous and detailed characterization of the structurala nd dynamic behavior of theset ransient intermediates in isolated environments, in which external interferences are absent,w ill help to reveali ntrinsic properties rele-vant to their biological activity.T he inherentb onding and conformationalf eatureso fc ysteine in its (de)protonated, [23,24] nitrosated, [25] and metal-tagged [26] forms have been previously interrogated both in the free amino acid and in the residue embodied in the glutathione peptide [27] by aj oint computational and experimental infrared multiple photon dissociation (IRMPD) assay.I RMPD spectroscopy,c oupled with ESI tandem mass spectrometry (MS/MS), is ap ivotalt ool to provide direct structural clues about gaseous (bio)molecular ions, [28][29][30][31][32][33] including (de)protonations ite, metal-binding patterns,a nd local intramolecular interactions in both native and modified amino acids and peptides, [34][35][36][37][38][39][40][41][42] DNA/RNA bases and nucleotides, [43][44][45] cluster ions, [46] and fragmentation products. [47] We now examine the intrinsic chemical properties and geometric features of the conjugate bases of cysteine sulfenic, sulfinic, and sulfonica cids, [cysSO x ] À (x = 1, 2, 3), by meanso fE SI/ MS-IRMPD spectroscopy in the highly informativem id-IR spectral range (750-1900 cm À1 )i nc ombination with ab initio...…”

Structure and further fragmentation of significant [a3 + Na − H]+ions from sodium-cationized peptides

“…It has been suggested that all available carbonyl oxygens are sodium binding sites in the most stable structures of sodium‐cationized peptides . As a result, the conformation of a sodiated peptide ion will be different from its protonated counterpart in which a proton often associates with one or two basic sites.…”