1. Purification and characterization of a protein with antifungal, antiproliferative, and HIV-1 reverse transcriptase inhibitory activities from small brown-eyed cowpea seeds
Guo-Ting Tian, Meng Juan Zhu, Ying Ying Wu, Qin Liu, He Xiang Wang, Tzi Bun Ng Biotechnol Appl Biochem. 2013 Jul-Aug;60(4):393-8. doi: 10.1002/bab.1102.
A 36-kDa protein, with an N-terminal sequence highly homologous to polygalacturonase (PG) inhibiting proteins, was isolated from small brown-eyed cowpea seeds. The protein was unadsorbed on diethylaminoethyl cellulose but adsorbed on both Affi-gel blue gel and SP-sepharose. It inhibited mycelial growth in the fungus Mycosphaerella arachidicola with an half-maximal (50%) inhibitory concentration (IC50 ) of 3.3 µM. It reduced [methyl-(3) H] thymidine incorporation into MBL2 lymphoma and L1210 leukemia cells with an IC50 of 7.4 and 5.4 µM, respectively. It inhibited human immunodeficiency virus type 1 (HIV-1) reverse transcriptase with an IC50 of 12.9 µM. However, it did not inhibit PG. The potent antifungal and antitumor activities of the protein suggest that it can be developed into an antifungal agent for combating M. arachidicola invasion in crops and an agent for cancer therapy in humans.
2. Purification and identification of a novel antifungal protein from Bacillus subtilis XB-1
Jianjun Ren, Wenhao He, Chunyu Li, Song He, Dongze Niu World J Microbiol Biotechnol. 2019 Sep 23;35(10):150. doi: 10.1007/s11274-019-2726-6.
This study aimed to characterize a powerful antifungal component from bacteria. Bacillus subtilis strain XB-1, which showed maximal inhibition of Monilinia fructicola, was isolated and identified, and an antifungal protein was obtained from it. Ammonium sulfate precipitation, ion exchange chromatography, and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) were used to purify and identify the proteins secreted by B. subtilis XB-1. Analyses revealed that purified fraction V had the strongest antifungal effect, with the largest pathogen inhibition zone diameter of 4.15 cm after 4 days (P < 0.05). This fraction showed a single band with a molecular weight of approximately 43 kDa in SDS-PAGE. Results from SDS-PAGE and liquid chromatography electrospray ionization tandem mass spectrometry analyses demonstrated that fraction V was likely a member of the chitosanase family. These results suggest that B. subtilis XB-1 and its antifungal protein may be useful in potential biocontrol applications.
3. Pr-1, a novel antifungal protein from pumpkin rinds
Seong-Cheol Park, Jung Ro Lee, Jin-Young Kim, Indeok Hwang, Jae-Woon Nah, Hyeonsook Cheong, Yoonkyung Park, Kyung-Soo Hahm Biotechnol Lett. 2010 Jan;32(1):125-30. doi: 10.1007/s10529-009-0126-y. Epub 2009 Sep 17.
A novel antifungal protein, M(r) = ca. 40 kDa, was isolated from pumpkin rind and designated Pr-1. When purified by anion exchange chromatography and HPLC, it inhibited growth of several fungi including Botrytis cinerea, Fusarium oxysporum, Fusarium solani and Rhizoctonia solani, as well as the yeast, Candida albicans, at 10-20 microM. It did not inhibit growth of Escherichia coli or Staphylococcus aureus even at 200 microM. Laser scanning microscopy of fungal cells exposed to rhodamine-labeled Pr-1 revealed that the protein accumulated and was localized on the cell surface. Uptake of the vital stain, SYTOX Green, was enhanced when fungal conidia were treated with Pr-1 suggesting that the protein has membrane permeabilization activity. Pr-1 was thermostable at 70 degrees C and did not lyse human red blood cells at 128 microM suggesting that the protein may be useful as an antifungal agent with little, if any human cytotoxicity.
