2M6P:
reference: The actinobacterial transcription factor RbpA binds to the principal sigma subunit of RNA polymerase., Tabib-Salazar A, Liu B, Doughty P, Lewis RA, Ghosh S, Parsy ML, Simpson PJ, O'Dwyer K, Matthews SJ, Paget MS, Nucleic Acids Res. 2013 Apr 19. PMID: 23605043

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).