Actinohivin, a Novel Anti-HIV Protein from an Actinomycete That Inhibits Syncytium Formation: Isolation, Characterization, and Biological Activities

• Published in: Biochemical and biophysical research communications 2001-03, Vol.282 (2), p.595-601
• Main Authors: Chiba, Harumi, Inokoshi, Junji, Okamoto, Megumi, Asanuma, Satoshi, Matsuzaki, Kei-ichi, Iwama, Minako, Mizumoto, Kiyohisa, Tanaka, Haruo, Oheda, Masayoshi, Fujita, Kazunobu, Nakashima, Hideki, Shinose, Mayumi, Takahashi, Yoko, Ōmura, Satoshi
• Format: Article
• Language: English
• Subjects: Actinohivin; Actinomycetales - chemistry; Actinomycetales - genetics; Actinomycetales - ultrastructure; AIDS; Amino Acid Sequence; Anti-HIV Agents - chemistry; Anti-HIV Agents - isolation & purification; Anti-HIV Agents - pharmacology; anti-HIV protein; Bacterial Proteins - genetics; Bacterial Proteins - isolation & purification; Bacterial Proteins - pharmacology; Cytopathogenic Effect, Viral - drug effects; Giant Cells - drug effects; Giant Cells - virology; HeLa Cells; HIV; HIV Infections - prevention & control; HIV-1 - drug effects; HIV-1 - pathogenicity; Human immunodeficiency virus; Humans; Macrophages - drug effects; Macrophages - virology; Microscopy, Electron, Scanning; Molecular Sequence Data; Molecular Weight; Sequence Homology, Amino Acid; Spectrometry, Mass, Electrospray Ionization; syncytium; T-Lymphocytes - drug effects; T-Lymphocytes - virology
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1006/bbrc.2001.4495

Blocking human immunodeficiency virus (HIV) entry into target cells is an important goal of HIV and acquired immune deficiency syndrome (AIDS) therapies. We have searched for anti-HIV substances from microorganisms using a syncytium formation assay system constructed with HeLa/CD4/Lac-Z and HeLa/T-env/Tat cells. We discovered a novel anti-HIV protein that inhibits syncytium formation, designated as actinohivin, from a cultured broth of a soil isolate, actinomycete strain K97-0003. ESI mass spectrometry of actinohivin isolated from the culture filtrate showed an ion with molecular mass of 12,520.3 Da. The amino acid sequence was determined by N-terminal Edman degradation of the intact protein and peptide fragments formed by endoproteinase digestions. Actinohivin consists of a 114-amino-acid chain that exhibits internal sequence triplication. Actinohivin inhibited both T-cell and macrophage tropic syncytium formation, with IC50 values of 60 and 700 nM, respectively, and the cytopathic effect of HIV-1IIIB in MT-4 cells, with IC50 value of 230 nM.