In order to determine whether the tryptic peptides isolated from
environmental samples matched those of M. luteus, the aconitate
hydratase protein sequence was downloaded from the genomic
sequence of M. luteus ATCC 4698 and SK58 (www.ncbi.nlm.nih.gov/
bioproject), and a virtual digest of the sequence was performed
with Protein Prospector software (prospector.ucsf.edu/prospector).
This software takes a known protein sequence and virtually cuts the protein with trypsin. Selecting the type of instrument used in the
software, in this case MALDI TOF MS, generates a list of all possible
m/z values, which could be present in the mass spectra. Mass
spectral peak lists (virtual spectra) obtained with the aid of Protein
Prospector were empirically compared with experimental spectra
of two M. luteus ATCC strains, S. hominis ATCC 27844, and 9 environmental
samples.