Crystal structures of carbamate kinase from Giardia lamblia bound with citric acid and AMP-PNP.
Crystal structures of carbamate kinase from Giardia lamblia bound with citric acid and AMP-PNP.
复制标题
DOI：
10.1371/journal.pone.0064004
复制
发表时间：
2013
期刊：
影响因子：
3.7
通讯作者：
Herzberg O
中科院分区：
文献类型：
--
作者：
Lim K;Kulakova L;Galkin A;Herzberg O
寄生虫蓝氏贾第鞭毛虫利用L-精氨酸二氢水解酶途径从L-精氨酸产生ATP。氨基甲酸激酶（CK）催化该途径的最后一步，将ADP和氨基甲酰磷酸转化为ATP和氨基甲酸铵。由于L-精氨酸途径是G.这种酶在包括人类在内的高等真核生物中不存在，因此是药物开发的潜在靶点。测定了G. Lamblia CK（glCK）与结合的配体。其中一种结构与一种不可水解的ATP类似物腺苷5′-腺苷酰-β，γ-亚氨基二磷酸（AMP-PNP）形成复合物，其分辨率为2.6 nm。第二种结构，在与柠檬酸结合在假定的氨基甲酰磷酸结合位点的复合物中，在2.1和2.4 μ m分辨率下以两种略微不同的状态测定。这些结构揭示了辅助结构域（氨基酸残基123-170）的构象灵活性，其表现出开放或闭合构象或结构紊乱，这取决于结合的配体。该结构还揭示了一个较小的构象变化的区域相关的AMP-PNP腺嘌呤结合位点。参与结合的蛋白质残基，连同过渡态的模型，表明催化遵循一个在线的，主要是解离的，磷酸转移反应机制，和封闭的灵活的辅助结构域是必需的，以保护过渡态从散装溶剂。
The parasite Giardia lamblia utilizes the L-arginine dihydrolase pathway to generate ATP from L-arginine. Carbamate kinase (CK) catalyzes the last step in this pathway, converting ADP and carbamoyl phosphate to ATP and ammonium carbamate. Because the L-arginine pathway is essential for G. lamblia survival and absent in high eukaryotes including humans, the enzyme is a potential target for drug development. We have determined two crystal structures of G. lamblia CK (glCK) with bound ligands. One structure, in complex with a nonhydrolyzable ATP analog, adenosine 5′-adenylyl-β,γ-imidodiphosphate (AMP-PNP), was determined at 2.6 Å resolution. The second structure, in complex with citric acid bound in the postulated carbamoyl phosphate binding site, was determined in two slightly different states at 2.1 and 2.4 Å resolution. These structures reveal conformational flexibility of an auxiliary domain (amino acid residues 123–170), which exhibits open or closed conformations or structural disorder, depending on the bound ligand. The structures also reveal a smaller conformational change in a region associated the AMP-PNP adenine binding site. The protein residues involved in binding, together with a model of the transition state, suggest that catalysis follows an in-line, predominantly dissociative, phosphotransfer reaction mechanism, and that closure of the flexible auxiliary domain is required to protect the transition state from bulk solvent.
登录
查看更多内容
影响因子：
2.9
作者：
Lim, Kap;Pullalarevu, Sadhana;Herzberg, Osnat
通讯作者：
Herzberg, Osnat
影响因子：
5.6
作者：
Ramón-Maiques, S;Marina, A;Rubio, V
通讯作者：
Rubio, V
DOI：
10.1093/protein/8.2.127
发表时间：
1995-02-01
期刊：
PROTEIN ENGINEERING
影响因子：
--
作者：
WALLACE, AC;LASKOWSKI, RA;THORNTON, JM
通讯作者：
THORNTON, JM
影响因子：
3.7
作者：
Gallego P;Planell R;Benach J;Querol E;Perez-Pons JA;Reverter D
通讯作者：
Reverter D
影响因子：
2.9
作者：
Hayward, S;Lee, RA
通讯作者：
Lee, RA