Assembly stoichiometry of bacterial selenocysteine synthase and SelC (tRNA(sec))

作者：Manzine Livia Regina; Balasco Serrao Vitor Hugo; Trambaioli da Rocha e Lima Luis Mauricio; de Souza Marcos Michel; Bettini Jefferson; Portugal Rodrigo Villares; van Heel Marin; Thiemann Otavio Henrique^*

来源：FEBS Letters, 2013, 587(7): 906-911.

DOI：10.1016/j.febslet.2013.02.014

• Selenocysteine synthase
• tRNA(sec)
• Stoichiometry

In bacteria selenocysteyl-tRNA(sec) (SelC) is synthesized by selenocysteine synthase (SelA). Here we show by fluorescence anisotropy binding assays and electron microscopical symmetry analysis that the SelA-tRNA(sec) binding stoichiometry is of one tRNA(sec) molecule per SelA monomer (1: 1) rather than the 1: 2 value proposed previously. Negative stain transmission electron microscopy revealed a D5 pointgroup symmetry for the SelA-tRNA(sec) assembly both with and without tRNA(sec) bound. Furthermore, SelA can associate forming a supramolecular complex of stacked decamer rings, which does not occur in the presence of tRNA(sec). We discuss the structure-function relationships of these assemblies and their regulatory role in bacterial selenocysteyl-tRNA(sec) synthesis.

• 出版日期2013-4-2
• 单位中国计量科学研究院