Identification of a Deoxyribonuclease I Inhibitor from a Phage-Peptide Library

• Published in: Molecules and cells 2005-02, Vol.19 (1), p.54-59
• Main Authors: Choi, S.J. (Kangnung National University, Gangneung, Republic of Korea), E-mail: [e-mail], Sperinde, Jeffrey J. (University of California at San Francisco, USA), Szoka Jr., Francis C. (University of California at San Francisco, USA)
• Format: Article
• Language: English
• Subjects: Actins - chemistry; Amino Acid Sequence; Antigens, CD1 - chemistry; Bacteriophages - genetics; Binding Sites; Deoxyribonuclease I - antagonists & inhibitors; Deoxyribonuclease I - chemistry; DNase I Inhibitor; Enzyme Inhibitors - isolation & purification; GENE; GENES; Peptide Library; Phage-Peptide Library; TERAPIA; THERAPEUTIQUE; THERAPY
• ISSN: 1016-8478
• DOI: 10.1016/S1016-8478(23)13136-0

Deoxyribonuclease Ⅰ (DNase Ⅰ) is a divalent cation dependent endonuclease and thought to be a significant barrier to effective gene delivery. The only known DNase Ⅰ-specific inhibitor is monomeric actin which acts by forming a 1:1 complex with DNase Ⅰ. Its use, however, is restricted because of tendency to polymerize under certain conditions. We screened two random phage peptide libraries of complexity 10∨8 and 10∨9 for DNase I binders as candidates for DNase Ⅰ inhibitors. A number of DNase Ⅰ-binding peptide sequences were identified. When these peptides were expressed as fusion proteins with Escherichia coli maltose binding protein, they inhibited the actin-DNase Ⅰ interaction (IC∧50 = 0.1-0.7 μM) and DNA degradation by DNase Ⅰ (IC∧50 = 0.8-8 μM).