6UU6

E. coli sigma-S transcription initiation complex with a 4-nt RNA and a UTP ("Old" crystal soaked with UTP, ddCTP, and dinucleotide ApG for 30 minutes)

RCSB PDB Core Operations are funded by the U.S. National Science Foundation (DBI-2321666), the US Department of Energy (DE-SC0019749), and the National Cancer Institute, National Institute of Allergy and Infectious Diseases, and National Institute of General Medical Sciences of the National Institutes of Health under grant R01GM157729.