2B9B:
reference: Structure of the parainfluenza virus 5 F protein in its metastable, prefusion conformation., Yin HS, Wen X, Paterson RG, Lamb RA, Jardetzky TS, Nature. 2006 Jan 5;439(7072):38-44. PMID: 16397490

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