来自积累鹅膏毒素的鹅膏菌属子实体的α-鹅膏毒肽抗性RNA聚合酶II

alpha-Amanitin-resistant RNA polymerase II from carpophores of Amanita species accumulating amatoxins.

作者信息

Johnson B C, Preston J F

出版信息

Biochim Biophys Acta. 1980 Mar 28;607(1):102-14. doi: 10.1016/0005-2787(80)90224-5.

Abstract

DNA-dependent RNA polymerase activities have been partially purified from carpophores of the amanitin (amatoxin)-accumulating species Amanita hygroscopica and Amanita suballiacea and the non-accumulating species Amanita brunnescens and Amanita alliacea. RNA polymerase II activities purified by ion-exchange chromatography were characterized with respect to ionic strength, template, and divalent metal ion requirements and sensitivities to inhibition by alpha-amanitin. The Ki values of alpha-amanitin for RNA polymerase II activities were: 2.0 . 10(-3) M for A. hygroscopica; 3.3 . 10(-3) M for A. suballiacea; 9.8 . 10(-6) M for A. brunnescens; 10.0 . 10(-6) M for A. alliacea. Further purification with DNA affinity chromatography of activities from A. suballiacea and A. brunnescens did not alter the apparent dissociation constants of alpha-amanitin from either enzyme. The correlation between amanitin sensitivity of RNA polymerase II and the quantity of amatoxins found in carpophores suggests these peptides may play a role in regulating transcription of messenger RNA during carpophore development.

摘要

已从积累鹅膏毒肽（鹅膏毒素）的物种 hygroscopica 鹅膏菌和近蒜味鹅膏菌的子实体以及不积累该毒素的物种浅黄鹅膏菌和蒜味鹅膏菌中部分纯化了依赖 DNA 的 RNA 聚合酶活性。通过离子交换色谱法纯化的 RNA 聚合酶 II 活性在离子强度、模板和二价金属离子需求以及对 α-鹅膏毒素抑制的敏感性方面进行了表征。α-鹅膏毒素对 RNA 聚合酶 II 活性的 Ki 值分别为： hygroscopica 鹅膏菌为 2.0×10⁻³ M；近蒜味鹅膏菌为 3.3×10⁻³ M；浅黄鹅膏菌为 9.8×10⁻⁶ M；蒜味鹅膏菌为 10.0×10⁻⁶ M。用 DNA 亲和色谱法进一步纯化近蒜味鹅膏菌和浅黄鹅膏菌的活性，并未改变 α-鹅膏毒素与这两种酶的表观解离常数。RNA 聚合酶 II 对鹅膏毒素的敏感性与子实体中发现的鹅膏毒素量之间的相关性表明，这些肽可能在子实体发育过程中调节信使 RNA 的转录中发挥作用。