Figure 1

Design of Mm-Cys-0, a cysteine-less chaperonin variant. (A) Strategy for the design of Cysteine-less protein variants. (B) Molecular architecture of group II chaperonin Mm-Cpn. The crystal structure of the closed state of MmCpn-RLS mutant bound to ADP-AlFx (PDBID: 3RUW²⁴. Highlighted are the equator of the complex (dashed line) and the three structural domains. A single subunit is shown in color with the seven cysteine residues rendered as spheres. Inset: cysteine clusters in the apical (top) and equatorial domains (bottom) (C) Design strategy of a cysteine-less MmCpn. Positions of seven Cys residues in Mm-Cpn WT are highlighted in yellow. (D) Extant sequences yielding the substitutions used to create the Cys-0 variant are shown along with the corresponding percentage identity and similarity between their sequence and MmCpn (see complete alignments in Supplemental Data). The sequence of MmCpn•Cys-0 (this work) is shown as well as the sequence of MmCpn∆Cys¹⁶.