(c) Substructure.

		Se-atom positions
Se atom	Assignment (residue No., chain†)	x	y	z	Occupancy	B (Å2)
Se1	206, B	−17.939	−13.852	−58.966	1.64	30.94
Se2	234, D	−64.915	−33.928	−27.483	1.45	35.04
Se3	88, B	−42.651	−46.722	−7.309	1.37	38.01
Se4	71, C	0.324	0.162	−0.150	1.47	33.56
Se5	206, D	−60.444	−48.554	−21.431	1.27	31.30
Se6	71, A	−32.458	−59.440	−83.338	0.89	24.26
Se7	239, A	−35.570	−38.874	−47.023	0.98	38.40
Se8	32, A	−47.427	−69.562	−79.399	1.04	34.19
Se9	45, D	−58.990	−28.139	−49.918	0.91	37.44
Se10	55, B	−56.321	−66.005	−80.110	0.96	38.51
Se11	45, B	−38.956	−47.261	−18.705	0.86	33.93
Se12	114, A	−41.256	−72.076	−65.133	0.72	31.91
Se13	88, D	−55.301	−29.252	−62.058	0.81	35.42
Se14	32, C	−23.146	−42.536	−8.722	0.79	31.52
Se15	20, B	−52.044	−15.465	−65.406	0.68	30.77
Se16	55, D	−47.423	−34.029	−71.423	0.64	33.47
Se17	114, C	−64.976	−48.206	−16.450	0.60	32.27
Se18	234, B	−32.520	−20.969	−59.005	0.48	27.50
Se19	239, C	−48.186	−20.825	−35.387	0.52	29.35
Se20	20, B	−51.989	−17.390	−67.308	0.53	27.02
Se21	20, D	−50.348	−58.173	−4.489	0.32	29.24
Se22	Cys210, B	−85.598	−67.823	−61.617	0.30	27.60

^†Chains A and B and chains C and D belong to CsuC and CsuE in the two molecules in the asymmetric unit, respectively.