Panaxagin, a new protein from Chinese ginseng possesses anti-fungal, anti-viral, translation-inhibiting and ribonuclease activities

Abstract

From the roots of the Chinese ginseng Panax ginseng a protein designated panaxagin with ribonuclease activity, but possessing a sequence distinct from ribonucleases previously reported from ginseng calluses, was isolated. The purification protocol employed comprised extraction with cold saline, (NH 4) 2SO 4 precipitation, ion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, ion exchange chromatography on SP-Sepharose, and gel filtration on Superdex 75 by fast protein liquid chromatography. The purified protein was composed of two identical subunits each with a molecular weight of 26 kDa. Its N-terminal amino acid sequence exhibits sites of similarity with the sequences of plant ribosome inactivating proteins and fungal ribonucleases. The spectrum of biological activities of panaxagin encompassed ribonuclease activity toward yeast transfer RNA, translation-inhibitory activity in a rabbit reticulocyte lysate system, and antifungal activity against fungi including Coprinus comatus and Fusarium oxysporum, but not against Rhizoctonia solani. In addition it displayed an inhibitory activity against human immunodeficiency virus reverse transcriptase and succinylation augmented this activity.