title: Calcaelin, a new protein with translation-inhibiting, antiproliferative and antimitogenic activities from the mosaic puffball mushroom Calvatia caelata.
abstract: Fresh fruiting bodies of the mushroom Calvatia caelata, commonly known as the mosaic puffball, were extracted with 10 mM Tris-HCl buffer (pH 7.2). The extract was subjected to a chromatographic procedure which has been successfully used to isolate ribosome-inactivating proteins from plants. It was first applied to an Affi-gel blue gel column previously equilibrated and eluted with 10 mM Tris-HCl buffer. The adsorbed fraction eluted with 1.5 M NaCl in the buffer was then purified by chromatography on DEAE-cellulose in the same buffer. The unadsorbed fraction yielded essentially a single peak when it was chromatographed on a column of Mono S. When the peak was then gel filtered on Superdex 75, it yielded a homogeneous peak with a molecular mass of 39 kDa. The protein, which was designated calcaelin, was dissociated into two subunits with a molecular mass of 19 kDa and 20 kDa, respectively, in SDS-polyacrylamide gel electrophoresis. The two bands exhibited the same N-terminal amino acid sequence which was somewhat similar to those of plant ribosome-inactivating proteins. A lesser degree of sequence homology to the fungal ribosome inactivating proteins alpha-sarcin and restrictocin was detected. Calcaelin inhibited translation in rabbit reticulocyte lysate with an IC 50 value of 4 nM and displayed a heat-labile RNase activity of 1.58 U/mg toward yeast tRNA. It exhibited an antimitogenic activity toward mouse splenocytes, and it reduced the viability of breast cancer cells. There was no hemagglutinating, antibacterial or antifungal activity.
authors.affiliation: Department of Biochemistry, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, PR China. biochemistry@uhk.edu.hk
authors.forename: Tzi Bun
authors.initials: TB
authors.lastname: Ng
authors.forename: Ying Wai
authors.initials: YW
authors.lastname: Lam
authors.forename: Hexiang
authors.initials: H
authors.lastname: Wang
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects; D001487:Basidiomycota; D002455:Cell Division / Q000187:drug effects*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D008826:Microbial Sensitivity Tests; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology*; D010940:Plant Proteins / Q000494:pharmacology*; D011817:Rabbits; D012260:Ribonucleases / Q000378:metabolism; D013154:Spleen / Q000166:cytology / Q000187:drug effects; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D000972:Antineoplastic Agents, Phytogenic; D010936:Plant Extracts; D010940:Plant Proteins; D012260:Ribonucleases