Fig. 3: Structure of DslA.

a Fold of catalytic region of DslA (R74 to terminal K254), N and C termini labeled, and disulfide bonds presented in stick form. b View ~90° from a, protein chain colored in rainbow progression from N terminus (blue) to C terminus (red), with secondary structure labeled (standard helices via letters A–G; unlabeled helices have been defined as smaller 3₁₀ helices, β-strands by numbers b1–4). The two acidic residues identified as participating in catalysis are presented in stick form. c Active site of DslA, with selected residues in stick form and hydrogen bonds as dashed blue lines. d Comparison between DslA (orange) and related lysozymes and glycoside hydrolases. The active-site floor β-sheet and any helices that match are represented in solid form (with DslA helix designation labeled, lettering includes “3” for the smaller 3₁₀ helices), with non-matching elements rendered transparently. GH numbering refers to CAZy nomenclature⁵⁰, and given examples have organism, PDB code and catalytic residues noted below the fold. Family GH23 demonstrates the strongest similarity to DslA, with just the core elements (helices D, F, β-sheet) matching for v-type lysozymes and chitosanases. e Zoomed-in active sites from d, with select active-site residues labeled (DslA numbered, other fold residues noted by a prime ′).