title: Characterization of the amino acids essential for the photo- and radioprotective effects of a Bowman-Birk protease inhibitor-derived nonapeptide.
abstract: The Bowman-Birk protease inhibitor has been reported to exert photo- and radioprotective activity. This effect was assigned to a cyclic nonapeptide sequence which is known to contain the amino acids responsible for the anti-chymotryptic activity of the BBI. The present study indicated that linearization of the nonapeptide resulted in a significant loss of anti-proteolytic activity, whereas the photo- and radioprotective capacity persisted. Substitution of the amino acids Leu or Ser of the nonapeptide, essential for the anti-proteolytic activity, with different amino acids, indicated that rather the hydrophobic features of the amino acids in this position than charge are critical to retain the photo- and radioprotective effect. These results suggest the existence of a bifunctional peptide sequence with anti-proteolytic and photo-/radioprotective capacity. However, the lack of correlation between the photo-/radioprotective activity and the anti-proteolytic activity within the peptides generated by modification of the linear nonapeptide argues for the existence of two closely colocalized domains within the nonapeptide responsible for photo-/radioprotection and protease inhibition.
authors.affiliation: Section of Radiobiology and Molecular Environmental Research, Department of Radiotherapy, Eberhard-Karls-University,72076 Tübingen, Germany. klaus.dittman@uni-tuebingen.de
authors.forename: K H
authors.initials: KH
authors.lastname: Dittmann
authors.forename: N
authors.initials: N
authors.lastname: Gueven
authors.forename: C
authors.initials: C
authors.lastname: Mayer
authors.forename: H P
authors.initials: HP
authors.lastname: Rodemann
mesh_terms: D019943:Amino Acid Substitution; D000596:Amino Acids / Q000737:chemistry*; D002460:Cell Line; D002999:Clone Cells; D005347:Fibroblasts / Q000737:chemistry* / Q000166:cytology; D006801:Humans; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011839:Radiation, Ionizing; D011837:Radiation-Protective Agents / Q000737:chemistry*; D020539:Sequence Analysis, Protein; D015842:Serine Proteinase Inhibitors / Q000737:chemistry / Q000378:metabolism*; D012867:Skin / Q000737:chemistry* / Q000166:cytology; D013329:Structure-Activity Relationship; D014358:Trypsin Inhibitor, Bowman-Birk Soybean / Q000378:metabolism*; D014466:Ultraviolet Rays / Q000009:adverse effects
chemical_list: D000596:Amino Acids; D011837:Radiation-Protective Agents; D015842:Serine Proteinase Inhibitors; D014358:Trypsin Inhibitor, Bowman-Birk Soybean