Tertiary Structure Formation in Simian Retrovirus Type 1 RNA Pseudoknot Increases Mechanical Stability and-1 Ribosomal Frameshifting Efficiency
作者单位:Nanyang Technological University
会议名称:《中国化学会-生物物理化学专业委员会第四届全国生物物理化学会议》
会议日期:2016年
学科分类:0710[理学-生物学] 07[理学] 071007[理学-遗传学]
关 键 词:RNA pseudoknot Ribosomal frameshifting Optical tweezers
摘 要:Many RNA viruses including Simian Retrovirus type 1(SRV-1) utilize minus-one ribosomal frameshifting as an alternative translation mechanism to generate stable ratios of structural and catalytic proteins. The detailed mechanism of minus-one ribosomal frameshifting is still not well understood. The SRV-1 frameshifting pseudoknot is located in the overlapping region of gag and pol genes and plays critical roles in stimulating frameshifting. We applied single-molecule force spectroscopy and steered molecular dynamics simulation to probe the mechanical stability of the wildtype SRV-1 frameshifting RNA pseudoknot and its mutants. In addition, we carried out ensemble thermal denaturation and native polyacrylamide gel electrophoresis studies. Our studies reveal that the minor-groove base triple formation in the pseudoknot enhances the structural compactness and mechanical stability. The-1 frameshifting efficiency is positively correlated with one-step unfolding rupture force and inversely correlated with the unfolding rate, consistent with the fact that ribosome is a force-generating molecular motor with helicase activity.