Sequence dependence of protein isoprenylation.
Sequence dependence of protein isoprenylation.
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DOI：
10.1016/s0021-9258(18)98729-6
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发表时间：
1991-08
期刊：
影响因子：
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通讯作者：
S. Moores;M. Schaber;S. Mosser;E. Rands;M. B. O'Hara;V. Garsky;M. Marshall;D. Pompliano;J. Gibbs
中科院分区：
文献类型：
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作者：
S. Moores;M. Schaber;S. Mosser;E. Rands;M. B. O'Hara;V. Garsky;M. Marshall;D. Pompliano;J. Gibbs
几种蛋白质已被证明是后修饰的一个特定的C-末端半胱氨酸残基的两个类异戊二烯生物合成途径的代谢产物，法呢基二磷酸或香叶基香叶基二磷酸。从牛脑的胞质组分中分离出三种负责蛋白质异戊二烯化的酶：法尼基蛋白转移酶（FTase），修饰细胞转化Ras蛋白，和两个香叶基-香叶基-蛋白转移酶，一个（GGT酶-I），其修饰具有异源三聚体GTP结合蛋白的γ-6亚基的C-末端氨基酸序列的嵌合Ras，另一个（GGT酶-II）修饰了酿酒酵母分泌型GTP酶蛋白YPT 1。在一个S。在缺乏FT酶活性的酿酒酵母菌株（ram 1）中，两种GGT酶均以野生型水平检测到。在一辆ram 2 S.在缺乏FT酶活性的酿酒酵母菌株中，GGT酶-I活性降低了67%，表明GGT酶-I和FT酶活性来源于不同的酶，但可能具有共同的遗传特征。对于FTase和GGT酶-I活性，蛋白质底物的C-末端氨基酸序列，CAAX盒，似乎包含与转移酶相互作用的所有关键决定因素。事实上，具有与FTase或GGT酶-I的蛋白质底物的C-末端序列相同的氨基酸序列的四肽通过充当替代底物来竞争蛋白质异戊二烯化。蛋白质底物的CAAX氨基酸序列的变化显着改变了它们作为FTase和GGTase-I底物的能力。此外，似乎FTase和GGT酶-I对CAAX蛋白底物具有互补的亲和力;也就是说，对于FTase来说是良好底物的CAAX蛋白通常对于GGT酶-I来说是不良底物，反之亦然。特别是，亮氨酸残基在C末端的影响是否CAAX蛋白是法尼基化或geranylgeranylated优先。YPT 1 C末端肽TGGGCC不与GGTase-II竞争或作为GGTase-II的底物，这表明GGTase-II和YPT 1之间的相互作用似乎取决于蛋白质底物序列的6个以上的C末端残基。这些结果确定了三种不同的异戊二烯基蛋白转移酶，每一种都是选择性的类异戊二烯和蛋白质底物。
Several proteins have been shown to be post-translationally modified on a specific C-terminal cysteine residue by either of two isoprenoid biosynthetic pathway metabolites, farnesyl diphosphate or geranylgeranyl diphosphate. Three enzymes responsible for protein isoprenylation were resolved chromatographically from the cytosolic fraction of bovine brain: a farnesyl-protein transferase (FTase), which modified the cell-transforming Ras protein, and two geranyl-geranyl-protein transferases, one (GGTase-I) which modified a chimeric Ras having the C-terminal amino acid sequence of the gamma-6 subunit of heterotrimeric GTP-binding proteins, and the other (GGTase-II) which modified the Saccharomyces cerevisiae secretory GTPase protein YPT1. In a S. cerevisiae strain lacking FTase activity (ram1), both GGTases were detected at wild-type levels. In a ram2 S. cerevisiae strain devoid of FTase activity, GGTase-I activity was reduced by 67%, suggesting that GGTase-I and FTase activities derive from different enzymes but may share a common genetic feature. For the FTase and the GGTase-I activities, the C-terminal amino acid sequence of the protein substrate, the CAAX box, appeared to contain all the critical determinants for interaction with the transferase. In fact, tetrapeptides with amino acid sequences identical to the C-terminal sequences of the protein substrates for FTase or GGTase-I competed for protein isoprenylation by acting as alternative substrates. Changes in the CAAX amino acid sequence of protein substrates markedly altered their ability to serve as substrates for both FTase and GGTase-I. In addition, it appeared that FTase and GGTase-I had complementary affinities for CAAX protein substrates; that is, CAAX proteins that were good substrates for FTase were, in general, poor substrates for GGTase-I, and vice versa. In particular, a leucine residue at the C terminus influenced whether a CAAX protein was either farnesylated or geranylgeranylated preferentially. The YPT1 C terminus peptide, TGGGCC, did not compete or serve as a substrate for GGTase-II, indicating that the interaction between GGTase-II and YPT1 appeared to depend on more than the 6 C-terminal residues of the protein substrate sequence. These results identify three different isoprenyl-protein transferases that are each selective for their isoprenoid and protein substrates.