1TIQ:
reference: Structural and functional evidence for Bacillus subtilis PaiA as a novel N1-spermidine/spermine acetyltransferase., Forouhar F, Lee IS, Vujcic J, Vujcic S, Shen J, Vorobiev SM, Xiao R, Acton TB, Montelione GT, Porter CW, Tong L, J Biol Chem. 2005 Dec 2;280(48):40328-36. Epub 2005 Oct 6. PMID: 16210326

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