Structure of Desulfitobacterium hafniense PylSc, a pyrrolysyl-tRNA synthetase
Structure of Desulfitobacterium hafniense PylSc, a pyrrolysyl-tRNA synthetase
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DOI：
10.1016/j.bbrc.2008.07.074
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发表时间：
2008-09-26
影响因子：
3.1
通讯作者：
Chan, Michael K.
中科院分区：
文献类型：
--
作者：
Lee, Marianne M.;Jiang, Ruisheng;Chan, Michael K.
吡咯赖氨酸是第22个基因编码的氨基酸，由PYS(一种吡咯氨酰-tRNA合成酶)带入其特定的tRNA上。在某些古老的产甲烷菌中，幽门螺杆菌被发现是单一的蛋白质，而在革兰氏阳性细菌中，幽门螺杆菌被分为两个独立的蛋白质，Pylsn和PylSc，对应于在产甲烷菌中发现的单一幽门螺杆菌蛋白的N-末端和C-末端结构域。以前的结晶学研究已经提供了与催化相关的古生代玛氏甲烷单胞菌C-末端截短部分的结构。在这里，我们报告了完整的Dhfniense PylSc蛋白的apo 2.1埃分辨结构，并将其与产甲烷物种的C末端截短的Pyls的结构进行了比较。在PylSc中，与吡咯赖氨酸环结合的疏水口袋比在古细菌酶中受到更多的限制；其他结构差异也很明显。(C)2008 Elsevier Inc.保留所有权利。
Pyrrolysine, the 22nd genetically-encoded amino acid, is charged onto its specific tRNA by PylS, a pyrrolysyl-tRNA synthetase. While PylS is found as a single protein in certain archaeal methanogens, in the Gram-positive bacterium Desulfitobacterium hafniense, PylS is divided into two separate proteins, PylSn and PylSc, corresponding to the N-terminal and C-terminal domains of the single PylS protein found in methanogens. Previous crystallographic studies have Provided the structure of a truncated C-terminal portion of the archaeal Methanosarcina mazei PylS associated with catalysis. Here, we report the apo 2.1 angstrom resolution structure of the intact D. hafniense PylSc Protein and compare it to structures of the C-terminal truncated PylS from methanogenic species. In PylSc, the hydrophobic pocket binding the ring of pyrrolysine is more constrained than in the archaeal enzyme; other structural differences are also apparent. (C) 2008 Elsevier Inc. All rights reserved.