Fig. (3) Mass spectroscopy analysis of the E. coli expressed proteins. MALDI-TOF spectra of Halobacterium MCM with (A) and without (C) intein were performed as described in “Material and Methods”. The 2158.16 and 2333.16 peaks were analyzed using MS/MS (C and D,respectively) as described in “Material and Methods”. Panel E shows the position of the peptide in the MCM amino acid sequence. Shaded areas show the location of the intein. The peptide corresponding to the 2158.16 peak is underlined and that for the 2333.16 peak is double underlined.