Search

Ammonium sulfate fractionation and divalent cation precipitation were applied to purify major contractile proteins from relaxed actomyosin extracted from molluscan catch muscle myofibrils, as a supramolecular complex composed of twitchin (TW), myosin (MY), and myorod (MR). The phosphorylation of twitchin by PKA-like kinase and the phosphorylation of myosin and myorod by myosin-associated kinase were found to play crucial role in the development of the catch state.

The intrinsic, as well as the extrinsic pathways are studied to explain the relation existing between apoptosis and histone H1 phosphorylation in Jurkat cells after the induction of apoptosis. The H1 subtypes are shown to get dephosphorylated on the addition of apoptosis.

Histone acetyltransferases CREB-binding protein (CBP), p300/CBP-associated factor (PCAF), and Tat-interactive protein, 60 kDa (Tip60) is experimented for their ability to in vitro acetylate high-mobility group box-containing proteins 1 and 2(HMGB-1 and -2) and the role of C-terminal domain on the pattern of acetylation as well as some properties of the modified truncated protein. It is found that the modifications in the acetylation pattern of HMGB-1 and -2 upon removal of the C-terminal tail are regarded as a means by which the acidic domain modulates some properties of these proteins.

In this study we have evaluated the suitability of a sheathless capillary electrophoresis—electrospray ionization mass spectrometry (CE—ESI-MS) interface with a porous tip as the nanospray emitter for use in peptide analysis. A positively charged capillary coating and 0.1% formic acid as background electrolyte were used for separation upstream from mass spectrometry characterization. The influence of the distance between emitter tip and MS inlet, ESI voltage applied, and of the electroosmotic flow (EOF) on electrospray performance and efficiency of the system was investigated in detail. Under optimized conditions, less than 30 amol of a model peptide (angiotensin I) was required for a detection in the base peak electropherogram and positive identification via tandem MS. Three different cationic capillary coatings were investigated for stability, resolution, and EOF and were found to enable reproducible separations by CE—ESI-MS. After optimizing MS settings, the effectiveness of the CE—ESI-MS method developed was compared with a state-of-the-art nano-liquid chromatography (LC)—ESI-MS method by analyzing Arg-C-digested rat testis linker histones with both systems. With comparable amounts of sample applied, the number of identified peptides increased by more than 60% when using CE—ESI-MS. We found that low molecular mass peptides (below 1400 Da) were preferentially identified by CE—ESI-MS, since this group of peptides poorly interacted with the reversed-phase material in the nano-LC system. Finally, total analysis time in LC—ESI-MS for three runs including equilibration was nearly 4 times longer than that of CE—ESI-MS: 246 versus 66 min. [ABSTRACT FROM AUTHOR]