id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	blockedby	blocking	notify_on_close	platform	project
397	Missing bonds in mmCIF 1tna	Tom Goddard	Greg Couch	"Opening 1tna mmCIF is missing many backbone bonds.  (And the missing bonds confuse smart display which ends up showing nothing.)

open 1tna
show
view

It displays correctly in Chimera 1.  Also the PDB format file for 1tna has the backbone bonds.

open 1tna format pdb
"	defect	closed	major		Input/Output		fixed						all	ChimeraX