Catalytic Intermediate Crystal Structures of Cysteine Desulfurase from the Archaeon Thermococcus onnurineus NA1

Table 2

Dihedral angles of the PLP pyridine ring and Schiff-base linkage in ToCDS protomers.

Protomer	A (internal)	A (external)	B (internal)	B (external)
Crystal I (NAT/NAT)	47.7	n.a.	45.0	n.a.
Crystal II (GD/GD)	69.1	−50.2	64.8	−53.6
Crystal III (IAA/GD)	53.3	−51.4	64.9	−50.0
Crystal IV (PSF/PSF)	38.3	n.a.	50.3	n.a.
	Average	Standard dev.	Average	Standard dev.
NAT and PSF	45.3	5.2	n.a.	n.a.
GD	66.2	2.5	−51.2	2.0
IAA	53.3	n.a.	−51.4	n.a.

Positive dihedral angle values are for internal aldimine in the NAT, PSF, and GD structures and negative dihedral angle values are for external aldimine in the GD structures and proposed external aldimine in the IAA structure. n.a.: not available.