FIGURE 3.

Structures of CV-N mutants. A, ribbon representation of the crystal structure of CVN^mutDB (PDB accession code 3CZZ). The two domains within each monomer in the asymmetric unit are colored green and pink and labeled by A, B, and A′, B′, respectively. Regions involved in mannose binding are shown in yellow. B, ribbon representation of the crystal structure of the domain-swapped dimer (CVN^ΔB)_dsd. The domains are colored green and pink and are labeled A, B for chain 1, and A′, B′ for chain 2. Regions involved in mannose binding are shown in yellow. C, analysis of monomeric CVN^mutDB and domain-swapped dimeric (CVN^ΔB)_dsd on a 20% polyacrylamide native gel. D, ribbon representation of the model structure of the intramolecular disulfide-linked monomeric variant (CVN^ΔA)_ssm. E, ribbon representation of model structure for the intermolecular disulfide-linked dimer (CVN^ΔA)_ssd. F, analysis of monomeric (CVN^ΔA)_ssm and dimeric (CVN^ΔA)_ssd on a 20% polyacrylamide SDS gel. Lane 1 shows the monomeric (CVN^ΔA)_ssm, lane 2 shows the dimeric (CVN^ΔA)_ssd, and lane 3 shows the dimeric (CVN^ΔA)_ssd after reduction with 5 mm dithiothreitol.