Ammonia channel couples glutaminase with transamidase reactions in GatCAB
Ammonia channel couples glutaminase with transamidase reactions in GatCAB
复制标题
DOI：
10.1126/science.1127156
复制
发表时间：
2006-06-30
期刊：
影响因子：
56.9
通讯作者：
Tanaka, Isao
中科院分区：
文献类型：
--
作者：
Nakamura, Akiyoshi;Yao, Min;Tanaka, Isao
谷氨酰胺基的形成。转移RNA（Gln-tRNA（Gln））在生命的三个领域中是不同的。大多数细菌采用间接途径通过作用于错酰化Glu-tRNA（Gln）的异源三聚体谷氨酰胺转移酶CAB（GatCAB）来产生Gln-tRNA（Gln）。在这里，我们描述了一系列的晶体结构的完整的GatCAB从金黄色葡萄球菌的载脂蛋白形式，并在复合物与谷氨酰胺，天冬酰胺，锰，和腺苷三磷酸类似物。两个确定的催化中心的转氨酶和转氨酶反应是显着遥远，但连接的亲水性氨通道30埃长。此外，我们表明，第一个U-A碱基对的受体茎和D环的tRNA（谷氨酰胺）作为身份要素的歧视所必需的GatCAB，并提出了一个完整的模型的整体协调反应合成Gin-tRNA（谷氨酰胺）。
The formation of glutaminyl. transfer RNA (Gln-tRNA(Gln)) differs among the three domains of life. Most bacteria employ an indirect pathway to produce Gln-tRNA(Gln) by a heterotrimeric glutamine amidotransferase CAB (GatCAB) that acts on the misacylated Glu-tRNA(Gln). Here, we describe a series of crystal structures of intact GatCAB from Staphylococcus aureus in the apo form and in the complexes with glutamine, asparagine, Mn2+, and adenosine triphosphate analog. Two identified catalytic centers for the glutaminase and transamidase reactions are markedly distant but connected by a hydrophilic ammonia channel 30 angstrom in length. Further, we show that the first U-A base pair in the acceptor stem and the D loop of tRNA(Gln) serve as identity elements essential for discrimination by GatCAB and propose a complete model for the overall concerted reactions to synthesize Gin-tRNA(Gln).