Isolation of unguilin, a cyclophilin-like protein with anti-mitogenic, antiviral, and antifungal activities, from black-eyed pea

Abstract

A protein designated unguilin was isolated from seeds of the black-eyed pea (Vigna unguiculata). It possesses a molecular weight of 18 kDa and an N-terminal sequence resembling that of cyclophilins and the cyclophilin-like antifungal protein from mung beans, and was adsorbed on Affi-gel blue gel and CM-Sepharose. Unguilin exerted an antifungal effect toward fungi including Coprinus comatus, Mycosphaerella arachidicola, and Botrytis cinerea. In addition, unguilin was capable of inhibiting human immunodeficiency virus-1 reverse transcriptase and the glycohydrolases a- and beta-glucosidases which are involved in HIV infection. Unguilin was devoid of lectin and ribonuclease activities. It inhibited methyl-3H-thymidine uptake by mouse splenocytes and it weakly inhibited translation in a rabbit reticulocyte lysate system. Unguilin resembles mungin in some aspects, but differs from it in others.