Protein surface mapping by chemical oxidation: structural analysis by mass spectrometry.
The solvent-accessible surface area of proteins is important in biological function for many reasons, including protein-protein interactions, protein folding, and catalytic sites. Here we present a chemical technique to oxidize amino acid side chains in a model protein, apomyoglobin, and subsequent elucidation of the effect of solvent accessibility on the sites of oxidation. Under conditions of low protein oxidation (zero to three oxygen atoms added per apomyoglobin molecule), we have positively identified five oxidation sites by liquid chromatography-tandem mass spectrometry and high-resolution Fourier transform mass spectrometry. Our results indicate that all oxidized amino acids, with the exception of methionine, have highly solvent-accessible side chains, but the rate of oxidation may not be dictated solely by solvent accessibility and amino acid identity.
Sharp
Joshua S
JS
Graduate School of Genome Science and Technology, The University of Tennessee-Oak Ridge National Laboratory, 1060 Commerce Park, Oak Ridge, TN 37830-8026, USA.
Becker
Jeffrey M
JM
Hettich
Robert L
RL
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis / Q000737:chemistry; D001059:Apoproteins / Q000032:analysis / Q000737:chemistry*; D007501:Iron / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009211:Myoglobin / Q000032:analysis / Q000737:chemistry*; D010084:Oxidation-Reduction; D010446:Peptide Fragments / Q000032:analysis; D011487:Protein Conformation; D012997:Solvents / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D013499:Surface Properties
D000596:Amino Acids; D001059:Apoproteins; D009211:Myoglobin; D010446:Peptide Fragments; D012997:Solvents; C010857:apomyoglobin; D007501:Iron