Schmitt E, Panvert M, Blanquet S, Mechulam Y
Laboratoire de Biochimie, Unité Mixte de Recherche No. 7654 du Centre National de la Recherche Scientifique, Ecole Polytechnique, F-91128 Palaiseau cedex, France.
EMBO J. 1998 Dec 1;17(23):6819-26. doi: 10.1093/emboj/17.23.6819.
The crystal structure of Escherichia coli methionyl-tRNAfMet transformylase complexed with formyl-methionyl-tRNAfMet was solved at 2.8 A resolution. The formylation reaction catalyzed by this enzyme irreversibly commits methionyl-tRNAfMet to initiation of translation in eubacteria. In the three-dimensional model, the methionyl-tRNAfMet formyltransferase fills in the inside of the L-shaped tRNA molecule on the D-stem side. The anticodon stem and loop are away from the protein. An enzyme loop is wedged in the major groove of the acceptor helix. As a result, the C1-A72 mismatch characteristic of the initiator tRNA is split and the 3' arm bends inside the active centre. This recognition mechanism is markedly distinct from that of elongation factor Tu, which binds the acceptor arm of aminoacylated elongator tRNAs on the T-stem side.
以2.8埃的分辨率解析了与甲酰甲硫氨酰 - tRNAfMet复合的大肠杆菌甲硫氨酰 - tRNAfMet转甲酰酶的晶体结构。该酶催化的甲酰化反应不可逆地使甲硫氨酰 - tRNAfMet参与真细菌的翻译起始。在三维模型中，甲硫氨酰 - tRNAfMet转甲酰酶填充在L形tRNA分子D茎侧的内部。反密码子茎环远离蛋白质。一个酶环楔入受体螺旋的大沟中。结果，起始tRNA特有的C1 - A72错配被分开，3'臂在活性中心内弯曲。这种识别机制与延伸因子Tu的识别机制明显不同，延伸因子Tu在T茎侧结合氨酰化延伸tRNA的受体臂。
