Human eosinophil major basic protein 2: Location of disulfide bonds and free sulfhydryl groups

Eosinophil granule major basic protein 2 (MBP2 or major basic protein homolog) is a paralog of major basic protein (MBP1) and, similar to MBP1, is cytotoxic and cytostimulatory in vitro. MBP2, a small protein of 13,433 Da molecular weight, contains 10 cysteine residues. Mass spectrometry shows two cystine disulfide linkages (Cys(20)-Cys(115) and Cys(92)-Cys(107)) and 6 cysteine residues with free sulfhydryl groups (Cys(2), Cys(23), Cys(42), Cys(43), Cys(68), and Cys(96)). MBP2, similar to MBP1, has conserved motifs in common with C-type lectins. The disulfide bond locations are conserved among human MBP1, MBP2 and C-type lectins.