Pananotin, a Potent Antifungal Protein from Roots of the Traditional Chinese Medicinal Herb Panax notoginseng

Abstract

The roots of the sanchi ginseng, Panax notoginseng, were extracted with an aqueous buffer. The extract was chromatographed on a CM-cellulose column to remove extraneous unadsorbed proteins. The adsorbed fraction was dialyzed and chromatographed on Affi-gel blue gel. The adsorbed fraction was again collected, dialyzed and applied on a column of Mono S. The second peak was dialyzed and chromatographed on an FPLC-gel filtration Superdex 75 column. An antifungal protein with an N-terminal sequence similar to those of chitinases was isolated from the first peak which had a molecular mass of 35 kDa. The sequence was distinctive in that the third and ninth highly conserved N-terminal residues (C and G) were replaced by H and M, respectively. The protein inhibited mycelial growth in Coprinus comatus, Physalospora piricola, Botrytis cinerea, and Fusarium oxysporum with an IC₅₀ of 100 nM, 1 μM, 630 nM and 560 nM, respectively. It inhibited cell-free translation with an IC₅₀ of 630 nM. Its antifungal and translation-inhibitory activities were more potent than those of previously reported antifungal proteins. It inhibited human immunodeficiency virus-1 reverse transcriptase by 35.8 % at 12.6 μM and 24.7 % at 1.26 μM.

Key words

Panax notoginseng - Araliaceae - antifungal protein - pananotin

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