STRUCTURE - FUNCTION AND KINETICS OF AAA+ ATPASES

这个子项目是众多研究子项目之一

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Why do defects in molecular machines (AAA+ ATPases) cause disease? These protein machines convert ATP hydrolysis into mechanical work. Both human cells and disease causing pathogens use this work to physically manipulate proteins or DNA to dismantle and reassemble membranes or other organelles, to replicate DNA and traverse cell division, to repair damaged proteins, or to regulate gene expression. We do not know how these molecular machines convert ATP hydrolysis into mechanical work. Our research focuses on one subset of AAA+ ATPAses, the bacterial-enhancer-binding proteins (EBPs) which use their ATPase activities to regulate transcription of genes needed for harmful activites (diseases, crop damage) or helpful ones (nitrogen fixation, environmental remediation, hydrogen or other metabolite production). In a prior project, we established two mechanisms for regulating the EBP ATPases, and began defining structural changes occuring in their catalytic cycle. The current project completes this latter goal and extends it to address the underlying mechanism via structure function studies of mutant forms of ATPase. Initial data for mutant proteins were collected, with final data collection scheduled for March of 2007. In addition, in 2006 data were collected for a novel complex of ATPase and its target protein (the s54 subunit of RNA polymerase), and control experiments for contrast variation SANS observations of complexes of promoter DNA with s54, s54 and ATPase, or s54, ATPase and the rest of RNA polymerase. Finally, preliminary data for structures of two additional EBP proteins and a eukaryotic chromatin remodeling protein were obtained.