期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2003
卷号：100
期号：5
页码：2278-2283
DOI：10.1073/pnas.0537525100
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Members of the protein family called ATPases associated with various cellular activities (AAA+) play a crucial role in transforming chemical energy into biological events. AAA+ proteins are complex molecular machines and typically form ring-shaped oligomeric complexes that are crucial for ATPase activity and mechanism of action. The Escherichia coli transcription activator phage shock protein F (PspF) is an AAA+ mechanochemical enzyme that functions to sense and relay the energy derived from nucleoside triphosphate hydrolysis to catalyze transcription by the {sigma}54-RNA polymerase. Closed promoter complexes formed by the {sigma}54-RNA polymerase are substrates for the action of PspF. By using a protein fragmentation approach, we identify here at least one {sigma}54-binding surface in the PspF AAA+ domain. Results suggest that ATP hydrolysis by PspF is coupled to the exposure of at least one {sigma}54-binding surface. This nucleotide hydrolysis-dependent presentation of a substrate binding surface can explain why complexes that form between {sigma}54 and PspF are transient and could be part of a mechanism used generally by other AAA+ proteins to regulate activity.
