Table 2. Comparison of Chi1 torsion angle of Cλ and Cκ cysteine residues involved in Lc-Hc disulfide bond from the complete hIgG1 Fab structures.

PDB ID	Lc Isotype	Cys1 chain	Cys1 residue	Chi1 (°)	Chi1 of the closest rotamer (°)	Deviation from the Chi1 of the closest rotamer (ΔChi1, °)
1AQK	λ	L	215	−130.87	−177.00	46.13
2HWZ	κ	L	213	179.32	−177.00	3.68
2R0L	κ	L	214	−54.79	−65.00	10.21
1Y0L	κ	L	214	174.94	−177.00	8.06
1FVE	κ	C	214	−178.97	−177.00	1.97
1RHH	κ	C	213	163.50	−177.00	19.50
1AJ7	κ	L	214	−61.07	−65.00	3.93
2EH7	κ	L	214	−174.63	−177.00	2.37
1FVD	κ	C	214	64.82	55.00	9.82
1B2W	κ	L	214	−175.33	−177.00	1.67
2OSL	κ	L	213	72.52	55.00	17.52
1DFB	κ	L	212	165.57	−177.00	17.43
1T3F	κ	A	214	−95.76	−65.00	30.76

The PDB entries were obtained from the disulfide bond database analysis in Table 1. The Chi1 angle calculation was performed using the rotamer database from program Coot.³⁷