title: Sequence homologies, hydrophobic profiles and secondary structures of cathepsins B, H and L: comparison with papain and actinidin.
abstract: The comparison of the amino acid sequences of 5 cysteine proteinases: papain, actinidin, rat cathepsins B and H and chicken cathepsin L, demonstrates a striking homology among their sequences. The N-terminal region (residues 1-70 in papain) and C-terminal region (residues 118-212 in papain) display the highest sequence homologies, whereas the lowest sequence homologies are observed in the middle region (residues 71-117 in papain); a segment where most insertions/deletions are observed. The highest sequence homology is observed between rat cathepsin H and chicken cathepsin L. As shown by X-ray studies, papain and actinidin have a clearly defined double domain structure. Each domain contains a core of non-polar side chains, which are retained in cathepsins B, H and L, except for the non-polar residue 203 of the core which is replaced by glutamic acid in cathepsin B. The percentage and the location of alpha-helix and beta-sheets of cathepsins B, H and L, assessed using the methods of Garnier et al. (1978, J. Mol. Biol. 120, 97-120) and Chou and Fasman (1974, Biochemistry 13, 222-245), show that the main ordered structures in papain and actinidin are probably retained in cathepsins B, H and L. The differences observed occur essentially in the middle region, a place where sequences display the lowest homologies and which is far removed from the active site.
authors.affiliation: SRV, INRA de Theix, Ceyrat, France.
authors.forename: E
authors.initials: E
authors.lastname: Dufour
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002401:Cathepsin B / Q000032:analysis; D056655:Cathepsin H; D056668:Cathepsin L; D002403:Cathepsins / Q000032:analysis; D003546:Cysteine Endopeptidases / Q000032:analysis*; D010450:Endopeptidases; D008969:Molecular Sequence Data; D010206:Papain / Q000032:analysis; D011487:Protein Conformation; D012689:Sequence Homology, Nucleic Acid
chemical_list: D002403:Cathepsins; D010450:Endopeptidases; D003546:Cysteine Endopeptidases; D002401:Cathepsin B; C018745:actinidain; D056668:Cathepsin L; C534280:Ctsl protein, rat; D056655:Cathepsin H; C534128:Ctsh protein, rat; D010206:Papain