6MTA:
reference: GTP hydrolysis is modulated by Arg34 in the RASopathy-associated KRAS(P34R)., Bera AK, Lu J, Lu C, Li L, Gondi S, Yan W, Nelson A, Zhang G, Westover KD, Birth Defects Res. 2020 Jun;112(10):708-717. doi: 10.1002/bdr2.1647. Epub 2020, Mar 18. PMID: 32187889

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