identified Ser-cisSer-Lys catalytic triad in which the peptide bond between Ser 131 and the
preceding residue Gly 130 is in a cis configuration. In order to characterize the property of
the novel triad, we have determined the structures of five mutant malonamidase E2 enzymes
that contain a Cys-cisSer-Lys, Ser-cisAla-Lys, or Ser-cisSer-Ala triad or a substitution of Gly
130 with alanine. Cysteine cannot replace the role of Ser 155 due to a hyper-reactivity of the …