Covalent chromatography of influenza virus membrane M1 protein on activated thiopropyl Sepharose-6B

Applications of reversible covalent chemistry in analytical sample preparation

Reversible covalent chemistry (RCC) adds another dimension to commonly used sample preparation techniques like solid-phase extraction (SPE), solid-phase microextraction (SPME), molecular imprinted polymers (MIPs) or immuno-affinity cleanup (IAC): chemical selectivity. By selecting analytes according to their covalent reactivity, sample complexity can be reduced significantly, resulting in enhanced analytical performance for low-abundance target analytes. This review gives a comprehensive overview of the applications of RCC in analytical sample preparation. The major reactions covered include reversible boronic ester formation, thiol-disulfide exchange and reversible hydrazone formation, targeting analyte groups like diols (sugars, glycoproteins and glycopeptides, catechols), thiols (cysteinyl-proteins and cysteinyl-peptides) and carbonyls (carbonylated proteins, mycotoxins). Their applications range from low abundance proteomics to reversible protein/peptide labelling to antibody chromatography to quantitative and qualitative food analysis. In discussing the potential of RCC, a special focus is on the conditions and restrictions of the utilized reaction chemistry.

[Differences in spatial structures of the influenza virus M1 protein in crystal, solution and virion]

Spatial structure of the influenza virus A/Puerto Rico/8/34 (PR8, subtype H1N1) M1 protein in a solution and composition of the virion was studied by tritium planigraphy technique. The special algorithm for modeling of the spatial structure is used to simulate the experiment, as well as a set of algorithms predicting secondary structure and disordered regions in proteins. Tertiary structures were refined using the program Rosetta. To compare the structures in solution and in virion, also used the X-ray diffraction data for NM-domain. The main difference between protein structure in solution and crystal is observed in the contact region of N- and M-domains, which are more densely packed in the crystalline state. Locations include the maximum label is almost identical to the unstructured regions of proteins predicted by bioinformatics analysis. These areas are concentrated in the C-domain and in the loop regions between the M-, N-, and C-domains. Analytical centrifugation and dynamic laser light scattering confirm data of tritium planigraphy. Anomalous hydrodynamic size, and low structuring of the M1 protein in solution were found. The multifunctionality of protein in the cell appears to be associated with its plastic tertiary structure, which provides at the expense of unstructured regions of contact with various molecules-partners.

The in situ spatial arrangement of the influenza A virus matrix protein M1 assessed by tritium bombardment

Intact influenza A virions were bombarded with thermally activated tritium atoms, and the intramolecular distribution of the label in the matrix protein M1 was analyzed to determine the in situ accessibility of its tryptic fragments. These data were combined with the previously reported x-ray crystal structure of the M1 fragment 2-158 [Sha, B. & Luo, M. (1997) Nat. Struct. Biol. 4, 239-244] and the predicted topology of the C domain (159-252) to propose a model of M1 arrangement in the virus particle.