LTQ FT ECD方法提高完整膜蛋白中跨膜结构域的肽段覆盖率

　　简介：Nearly one third of the proteome is believed to consist of integral membrane proteins of biological membrane bilayers that compartmentalize living cells and as such have been identified as important drug targets (Lehnert et al., 2004). Because of their unique chemical nature, these proteins are difficult to characterize with conventional enzymatic digestion and LC-MS/MS analyses of the subsequent peptides. As an alternative approach, “top-down” protein characterization has been developed. Top-down protein characterization relies on high-resolution Fouriertransform mass spectrometry (FT-MS) to accurately measure the mass of intact protein molecular ions, followed by their fragmentation in the mass spectrometer without prior digestion. This makes it possible to obtain primary structure information for unambiguous identification and characterization of protein covalent modifications (Kelleher et al., 1999; Kelleher, 2004).

　　仪器：LTQ FT/ECD

　　结论：Clearly, we have shown that activated ion ECD is a powerful tool for sequencing hydrophobic proteins of the type isolated from cellular membranes. Conventional electron capture dissociation has been shown to preserve labile post translational modifications including phosphorylation and glycosylation (Mirgorodskaya et al., 1999; Shi et al., 2001). This study suggests that ECD when combined with IR laser activation can be a powerful tool to characterize covalent modifications in the transmembrane loops of the hydrophobic proteins.