ADP-RIBOSYLATION CYCLES

单腺苷二磷酸核糖化是蛋白质的翻译后修饰 它参与了细菌毒素的作用和调节 细胞过程。精氨酸、半胱氨酸和丙氨酸特异的ADP- 核糖基转移酶已在动物组织中被发现。NAD：精氨酸 ADP-核糖基转移酶和ADP-核糖精氨酸水解酶，催化 推测的ADP-核糖化循环的正臂和反臂有 在哺乳动物组织中被发现。ADP-核糖精氨酸水解酶 从火鸡红细胞和大鼠脑中提纯并克隆其cDNA 从后一种组织中。在精氨酸特异性ADP的情况下- 兔骨骼肌核糖基转移酶的部分纯化 报道了膜的存在。为了定义这种酶的结构，它是 纯化、微测序和克隆。 兔骨骼肌精氨酸特异性ADP-核糖基转移酶 经连续五步层析纯化约215,000倍。在……上面 经高效液相色谱纯化的胰多肽的氨基酸序列基础， 合成了简并的寡核苷酸引物，并将其应用于 聚合酶链式反应(PCR)为基础的程序，以产生CDNA。一个 根据聚合酶链式反应产生的序列，使用特定的探针来筛选 兔骨骼肌库。复合序列，从 文库筛选和CDNA 5‘端的快速扩增， 包含一个981个碱基对的开放阅读框，编码36,134-Da 蛋白。表达载体转化大肠杆菌细胞的研究 含有转移酶特异序列表达转移酶活性。 一种转移酶特异的寡核苷酸探针识别4千碱基的mRNA 主要在兔骨骼肌和心肌中表达。根本没有 肌肉推导的氨基酸序列的扩展相似性 转移酶和几种ADP核糖化细菌毒素。

Mono-ADP-ribosylation is a posttranslational modification of proteins which is involved in the action of bacterial toxins and in the regulation of cellular processes. Arginine-, cysteine- and aparagine-specific ADP- ribosyltransferases have been identified in animal tissues. NAD:arginine ADP-ribosyltransferase and ADP-ribosylarginine hydrolases, which catalyze the forward and reverse arms of a putative ADP-ribosylation cycle, have been identified in mammalian tissues. ADP-ribosylarginine hydrolase was purified from turkey erythrocytes and rat brain and its CDNA was cloned from the latter tissue. In the case of the arginine-specific ADP- ribosyltransferase, partial purification from rabbit skeletal muscle membranes was reported. To define the structure of this enzyme, it was purified, microsequenced, and cloned. Rabbit skeletal muscle arginine-specific ADP-ribosyltransferase was purified about 215,000-fold by sequential five-step chromatography. On the basis of the amino acid sequences of HPLC-purified tryptic peptides, degenerate oligonucleotide primers were synthesized and used in a polymerase chain reaction (PCR)-based procedure to generate CDNA. A specific probe, based on PCR-generated sequence, was used to screen a rabbit skeletal muscle library. A composite sequence, obtained from library screening and rapid amplification of the 5' end of the CDNA, contained a 981-base-pair open reading frame, encoding a 36,134-Da protein. Escherichia coli cells transformed with an expression vector containing transferase-specific sequence expressed transferase activity. A transferase-specific oligonucleotide probe recognized a 4-kilobase MRNA expressed primarily in rabbit skeletal and cardiac muscle. There was no extended similarity in deduced amino acid sequences of the muscle transferase and several ADP-ribosylating bacterial toxins.