1Y5Y:
reference: How an enzyme binds the C1 carrier tetrahydromethanopterin. Structure of the tetrahydromethanopterin-dependent formaldehyde-activating enzyme (Fae) from Methylobacterium extorquens AM1., Acharya P, Goenrich M, Hagemeier CH, Demmer U, Vorholt JA, Thauer RK, Ermler U, J Biol Chem 2005 Apr 8;280(14):13712-9. Epub 2005 Jan 4. PMID: 15632161

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