FIG. 3.

Peptide sequences of purified 18-kDa protein. Protein was purified as indicated in Materials and Methods. The lightly staining band on an SDS-polyacrylamide gel was excised and sequenced by mass tandem spectrometry. After trypsin digestion, two peptide sequences were obtained. Brackets indicate that the amino acid has been identified with reasonable confidence; an asterisk indicates that the amino acid is isobaric and cannot be unambiguously differentiated by mass spectrometric sequencing. All other amino acids are assigned with the highest confidence.