Fig. 5. Fxna functional domains. The deduced amino acid sequence is shown in capital letters and the nucleotide sequence in lower case letters. The peptidase unit is underlined; the catalytic residues (Asp 201, Glu 245) are circled, and the metal-binding amino acids (His 199, Asp 211, Glu 246, Glu 272 and His 348) within squares. Heavy underlining identifies the polyadenylation signal.