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. Structural studies of proteins and nucleic acids and the complexes they make that are involved in executing Crick's Central Dogma of Molecular Biology are the subjects of our ongoing studies. The structures being pursued include complexes between the components of the bacterial replisome - DnaB helicase complexed with primase and DNA as well as complexes with a fragment of Tau;E. coli RNA polymerase complexed with DNA;CAP without ligands and CAP with cAMP bound to DNA with RNA polymerase;novel aminacyl-tRNA synthetases complexed with substrates;structures of the 70S ribosome complexed with substrates, factors, or antibiotics;complexes between the 50S ribosomal subunit and antibiotics;structural studies of the eukaryotic ribosomes.