Verification of Ribosomal Proteins of Aspergillus fumigatus for Use as Biomarkers in MALDI-TOF MS Identification

Abstract

We have previously proposed a rapid identi method for bacterial strains based on the pro of their ribosomal subunit proteins (RSPs), observed using matrix-assisted laser desorption/ionization time-of-mass spectrometry (MALDI-TOF MS). is method can perform phylogenetic characterization based on the mass of housekeeping RSP biomarkers, ideally calculated from amino acid sequence informa-tion registered in public protein databases. With the aim of extending its of application to medical my-cology, this study investigates the actual state of information of RSPs of eukaryotic fungi registered in pub-lic protein databases through the characterization of ribosomal protein fractions extracted from genome-sequenced Aspergillus fumigatus strains Af293 and A1163 as a model. In this process, we have found that the public protein databases harbor problems. RSP names are in confusion, so we have provisionally uni them using the yeast naming system. e most serious problem is that many incorrect sequences are registered in the public protein databases. Surprisingly, more than half of the sequences are incorrect, due chie to mis-annotation of exon/intron structures. errors could be corrected by a combination of in silico inspection by sequence homology analysis and MALDI-TOF MS measurements. We were also able to con conserved post-translational modi in eleven RSPs. A these veri the masses of 31 expressed RSPs under 20,000 Da could be accurately con ese RSPs have a potential to be useful biomarkers for identifying clinical isolates of A. fumigatus. Please cite this article as: Mass Spectrom (Tokyo) 2016; 5(1): A0049