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Spektrometria mas w analizie białek i peptydów : znaczniki jonizacyjne

Bąchor R., Biernat M., Cebrat M., Kijewska M., Kluczyk A., Kuczer M., Paluch A., Waliczek M., Wierzbicka M., Stefanowicz P., Szewczuk Z.

Wiadomości Chemiczne

2018

[Z] 72, 7-8

609--633

High sensitivity, accuracy, and ability to provide structural information makes mass spectrometry (MS) the method of choice for both qualitative and quantitative analysis in proteome research. Peptide sequencing by tandem mass spectrometry (MS/MS) was successfully applied to discover new peptide sequences and modifications. Insufficient ionization of some peptides is one of the main limitations of MS- based peptide identification. The development of sensitive detection techniques for the efficient analysis of such samples is very important. Differences in ionizability cause difficulties in quantification studies, which could be overcome by derivatization of peptides to improve both the detectability and the selectivity of an analysis. Incorporation of ionization markers and isotopic labels (particularly the isobaric tags) is often used for this reason. Isobaric labeling reagents (including commercially available iTRAQ, TMT, DiLeu and DiART) have found a wide application in quantitative proteomics. Mass spectrometry is a very good tool for the determination of posttranslational modifications (PTMs), but the modified proteins are usually present in low concentrations. The development of ionization tags specific to a particular PTM and suitable for sensitive analysis of the modified proteins is required. For the analysis of phosphorylated peptides, a combination of β-elimination and the reaction of resulting α,β-dehydroamino acid residues with the nucleophilic thiol group could be used to detect a labile PTM. Such reaction may be used to introduce derivatizing reagents at the original site of phosphorylation, to enhance ionization in MS analysis. Glycation and glycosylation of proteins are other very important PTMs associated with many natural processes as well as diseases. We have designed and synthesized bifunctional quaternary ammonium salt derivatives of phenylboronic acids for selective detection of carbohydrates and peptide-derived Amadori products by ESI-MS. The attachment of a fixed charge (e.g. in a form of a quaternary ammonium salt) to the amino groups in peptides leads to the enhancement of a precursor ion signal in mass spectra. We have developed several new QAS-containing ionization reagents including bicyclic tags with DABCO, ABCO or azoniaspiro groups. It is worth noting that 2,4,6-substituted pyrylium salts react with amino groups in peptides introducing a stable positive charge and improve peptide detection by MS. The newly developed ionization tags were successfully applied for the analysis of OBOC combinatorial libraries as well as for studying possible biomarkers of preeclampsia, a pregnancy disorder.

Wpływ fosforylacji na agregację cystatyny z białka jaja kurzego

Horowski A., Gołąb K., Juszczyńska K., Trziszka T., Polanowski A., Gburek J.

Przemysł Chemiczny

2013

T. 92, nr 4

551-554

Zastosowanie cyklicznych, 5-członowych odczynników fosforylujących oraz fosfitylujących w chemicznej syntezie biofosforanów

Olesiak M., Okruszek A.

Wiadomości Chemiczne

2009

[Z] 63, 5-6

437-459

Cyclic, 5-membered derivatives of three- and tetracoordinated phosphorus constitute an important group of organophosphorus compounds in light of their increased reactivity towards nucleophilic reagents. This surprising reactivity is caused by steric strain present in 5-membered heterocyclic ring, which is then released on formation of reaction intermediates possessing pentacovalent phosphorus atom. This problem was thoroughly analyzed by Westheimer in his classical paper [13]. The title cyclic compounds found an application in the chemical synthesis of biophosphates such as phospholipid derivatives [15-17, 19-21] or nucleoside phosphates [14, 18], however, in spite of numerous efforts (especially by the groups of Ugi and Ramirez) their applicability to efficient formation of internucleotide linkage was rather limited [22-26]. Further development of this matter was achieved by Stec and coworkers [27], who in 1991 applied appropriately protected P-chiral nucleoside- -3'-O-(2-thiono-1,3,2-oksathiaphospholane)s for the synthesis of stereoregular oligo(nucleoside phosphorothioate)s. In fact, the oxathiaphospholane method was for many years a unique successful approach to stereocontrolled synthesis of phosphorothioate analogs of oligonucleotides. The method was later modified and applied for preparation of other phosphorothioate analogs of nucleotides [29-36], including compounds not containing sulphur [37-39]. Further modification led to so called dithiaphospholane approach, allowing an efficient synthesis of oligo(nucleoside phosphorodithioate)s [40] and other phosphorodithioate analogs of nucleotides [41-44]. An alternative approach to the synthesis of stereoregular oligo(nucleoside phosphorothioate)s, involving an application of P-chiral nucleoside oxazaphospholidine derivatives had at first a limited success (Agrawal et al. [45-47], Beaucage et al. [48]), however, recent achievements of Wada et al. [49] made compounds of this series efficient precursors for stereocontrolled synthesis of phosphorothioate analogs of oligonucleotides.