THE METHYLATED DNA-BINDING PROTEIN-2-H1 (MDBP-2-H1) CONSISTS OF HISTONE H1 SUBTYPES WHICH ARE TRUNCATED AT THE C-TERMINUS

The methylated DNA binding protein-2-H1 (MDBP-2-H1), present in rooste r liver, is a member of the histone H1 family which inhibits transcrip tion by binding selectively to methylated promoters, Here we have dete rmined the primary structure of MDBP-2-H1. A comparison between histon e H1 and MDBP-2-H1 was achieved by analyzing reversed phase HPLC-purif ied and V8-digested proteins by mass spectrometry and/or microsequenci ng, In rooster liver the most abundant histone H1 subtypes are H1 01 a nd H1 11L, Similarly, MDBP-2-H1 contains the same subtypes of histone H1, The histone H1 subtype H1 01 in MDBP-2-H1 has 150 amino acids, whe reas the full-size histone H1 01 is 218 amino acids, The difference in mass between the two proteins is explained by C-terminal truncation o f histone H1 01.