Evaluation of mass spectrometric data using principal component analysis for determination of the effects of organic lakes on protein binder identification.
Matrix-assisted laser desorption/ionisation-time of flight (MALDI-TOF) mass spectrometry is commonly used for the identification of proteinaceous binders and their mixtures in artworks. The determination of protein binders is based on a comparison between the m/z values of tryptic peptides in the unknown sample and a reference one (egg, casein, animal glues etc.), but this method has greater potential to study changes due to ageing and the influence of organic/inorganic components on protein identification. However, it is necessary to then carry out statistical evaluation on the obtained data. Before now, it has been complicated to routinely convert the mass spectrometric data into a statistical programme, to extract and match the appropriate peaks. Only several 'homemade' computer programmes without user-friendly interfaces are available for these purposes. In this paper, we would like to present our completely new, publically available, non-commercial software, ms-alone and multiMS-toolbox, for principal component analyses of MALDI-TOF MS data for R software, and their application to the study of the influence of heterogeneous matrices (organic lakes) for protein identification. Using this new software, we determined the main factors that influence the protein analyses of artificially aged model mixtures of organic lakes and fish glue, prepared according to historical recipes that were used for book illumination, using MALDI-TOF peptide mass mapping.
Department of Biochemistry and Microbiology, University of Chemistry and Technology, Technická 3, 166 28 Prague 6, Prague, Czech Republic.
Stepanka
S
Hrdlickova Kuckova
Department of Biochemistry and Microbiology, University of Chemistry and Technology, Technická 3, 166 28 Prague 6, Prague, Czech Republic.
Gabriela
G
Rambouskova
Department of Biochemistry and Microbiology, University of Chemistry and Technology, Technická 3, 166 28 Prague 6, Prague, Czech Republic.
Radovan
R
Hynek
Department of Computing and Control Engineering, University of Chemistry and Technology, Technická 3, 166 28 Prague 6, Prague, Czech Republic.
Pavel
P
Cejnar
Cologne Institute of Conservation Sciences, Ubierring 40, D-50678, Köln, Germany.
Doris
D
Oltrogge
Cologne Institute of Conservation Sciences, Ubierring 40, D-50678, Köln, Germany.
Robert
R
Fuchs
D000818:Animals; D003300:Copper / Q000737:chemistry; D007313:Insecta / Q000737:chemistry; D010150:Paint; D010151:Paintings; D025341:Principal Component Analysis; D011506:Proteins / Q000032:analysis*; D012815:Signal Processing, Computer-Assisted; D012984:Software; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D017550:Spectroscopy, Fourier Transform Infrared; D013997:Time Factors
D011506:Proteins; D003300:Copper
artificial ageing; infrared spectroscopy with Fourier transformation; matrix-assisted laser desorption/ionisation - time of flight mass spectrometry; organic lakes; principal component analysis