MALDI Peptide Mapping for Fast Analysis in Protein Footprinting.

Although protein footprinting results are commonly obtained by ESI-based LC-MS/MS, a more rapid-turnaround alternative approach is desirable to expand the scope of protein footprinting and facilitate routine analysis such as monitoring protein high order structure in quality control or checking epitope maps. Considering that MALDI is a faster procedure that can be easily adapted for high-throughput analysis, we explore here the feasibility of developing a MALDI-based analysis "portfolio" of bottom-up peptide mass mapping for footprinting. The approach was applied to several model proteins that were submitted to two footprinting strategies, FPOP and GEE labeling, and their performance was evaluated.

Toward a MALDI in-source decay (ISD) method for top-down analysis of protein footprinting.

Irreversible protein footprinting is a mass spectrometry-based approach in which solvent-accessible sites of a protein are modified to assess high-order protein structure. Structural insights can be gained by determining the position and extents of modification. The usual approach to obtain the "footprint" is to analyze the protein through bottom-up LC-MS/MS.

Binding of red form of Orange Carotenoid Protein (OCP) to phycobilisome is not sufficient for quenching.

The Orange Carotenoid Protein (OCP) is responsible for photoprotection in many cyanobacteria. Absorption of blue light drives the conversion of the orange, inactive form (OCP) to the red, active form (OCP). Concomitantly, the N-terminal domain (NTD) and the C-terminal domain (CTD) of OCP separate, which ultimately leads to the formation of a quenched OCP-PBS complex.

Isolation of Amine Derivatives of (ZnSe) and (CdTe). Spectroscopic Comparisons of the (II-VI) and (II-VI) Magic-Size Nanoclusters.

The spectroscopically observed magic-size nanoclusters (ZnSe) and (CdTe) are isolated as amine derivatives. The nanoclusters [(ZnSe)( n-octylamine)(di- n-octylamine)] and [(CdTe)( n-octylamine)(di- n-pentylamine)] are fully characterized by combustion-based elemental analysis, UV-visible spectroscopy, IR spectroscopy, and mass spectrometry. Amine derivatives of both (ZnSe) and (CdTe) are observed to convert to the corresponding (ZnSe) and (CdTe) derivatives, indicating that the former are kinetic products and the latter thermodynamic products, under the conditions employed.