Extended Data Figure 1. TEM characterization of ^C98RhuA and ^H63/H98RhuA self-assembly under non-optimal conditions.

a, 25 μM ^C98RhuA was incubated at 4 °C under air exposure for 1 day; the solution contained 20 mM TRIS (pH 8) and no reductants/oxidants. b, 25 μM ^H63/H98RhuA was incubated in the presence of 1 mM ZnCl₂ at 4 °C for 1 day; the solution contained 20 mM MOPS (pH 7).