Denatured human alpha-defensin attenuates the bactericidal activity and the stability against enzymatic digestion

Elsevier, Tanabe, Hiroki ; Ayabe, Tokiyoshi ; Maemoto, Atsuo ; Ishikawa, Chisato ; Inaba, Yuhei ; Sato, Ryu ; Moriichi, Kentaro ; Okamoto, Kotaro ; Watari, Jiro ; Kono, Toru ; Ashida, Toshifumi ; Kohgo, Yutaka, Biochemical and Biophysical Research Communications, 358(1), 2007, 349-335. authorα-Defensin is an antimicrobial peptide which plays an important role in innate immunity. Human defensin (HD)-5 is stored in the Paneth cells of the small intestine as a pro-form and is cleaved by trypsin, which is co-secreted from the Paneth cell granules. The mature HD-5 is protected from further digestion by the proteolysis enzyme. We generated both recombinant HD-5 and proHD-5, and the reduced form of each peptide in order to determine their physiological roles of the disulfide bonds. The reduced proHD-5 attenuated the bactericidal activity and the stability against the trypsin digestion. Human defensin was protected from the enzymatic degradation by disulfide bridges. We further purified the HD-5 with a disulfide variation in the small intestine of Crohn’s disease patients. The HD-5 was sensitive to the trypsin treatment. These observations evidently predict that a defensin deficiency may be caused by a disulfide disorder in the disease