Figure 1.

Overview of the FenA structure. (A) Stereo view of the tertiary structure of FenA, depicted as a cartoon model with magenta β strands, cyan α helices (numbered sequentially), and blue 3₁₀ helices. The N and C termini are indicated in italics. Three manganese ions in the active site (M1, M2, M3) and a fourth manganese (M4) engaged by the β3–β4 loop are shown as magenta spheres. (B) The secondary structure elements of FenA are shown above the FenA amino acid sequence, labeled sequentially and colored as in panel A. The eight acidic amino acid side chains that bind the active site metals are denoted by red dots below FenA the primary structure.