Disassembly intermediates of RbsD protein remain oligomeric despite the loss of an intact secondary structure  

作　　者：FENG YongJun1, ZHANG Meng2, HU MingXi1, ZHENG Jie1, JIAO WangWang2 & CHANG ZengYi2 1 School of Life Science, Beijing Institute of Technology, Beijing 100081, China 2 School of Life Sciences, National Laboratory of Protein Engineering and Plant Genetic Engineering, Center for Protein Science, Peking University, Beijing 100871, China 

出　　处：《Science China(Life Sciences)》2009年第11期997-1002,共6页中国科学（生命科学英文版）

基　　金：Supported by the National Natural Science Foundation of China (Grant Nos. 30570355, 30670022 and 30870055);the National Key Basic Research Foundation of China (Grant Nos 2006CB806508 and 2006CB910300)

摘　　要：Many proteins exist as homo-oligomers in living organisms wherein the change of oligomeric status apparently serves as an effective means for modulating their biological activities. We have previously reported that the homo-decameric RbsD from Escherichia coli undergoes stepwise disassembly and non-stepwise reassembly. Here the structural status of the urea-induced RbsD disassembly intermediates was examined, mainly using urea-containing polyacrylamide gel electrophoresis and chemical cross-linking. Such intermediates were found to remain oligomeric while losing their intact secondary structures. Such disassembly intermediates were able to effectively refold when the concentration of the urea denaturant was reduced to a lower level, or to refold/reassemble into the native decamers when urea was completely removed, as detected by non-denaturing polyacrylamide gel electrophoresis. These novel observations strongly suggest that the assembly of oligomeric proteins may occur before the completion of subunit folding.Many proteins exist as homo-oligomers in living organisms wherein the change of oligomeric status apparently serves as an effective means for modulating their biological activities. We have previously reported that the homo-decameric RbsD from Escherichia coli undergoes stepwise disassembly and non-stepwise reassembly. Here the structural status of the urea-induced RbsD disassembly intermediates was examined, mainly using urea-containing polyacrylamide gel electrophoresis and chemical cross-linking. Such intermediates were found to remain oligomeric while losing their intact secondary structures. Such disassembly intermediates were able to effectively refold when the concentration of the urea denaturant was reduced to a lower level, or to refold/reassemble into the native decamers when urea was completely removed, as detected by non-denaturing polyacrylamide gel electrophoresis. These novel observations strongly suggest that the assembly of oligomeric proteins may occur before the completion of subunit folding.

关 键 词：RbsD oligomeric PROTEIN oligomeric INTERMEDIATE REFOLDING reassembly 

分 类 号：Q51[生物学—生物化学]