Structure of Ddn, the Deazaflavin-Dependent Nitroreductase from Mycobacterium tuberculosis Involved in Bioreductive Activation of PA-824

Abstract

The original article unfortunately has an author error in the units for k cat and k cat /K m on page 108. In Table 2, row 2, all k cat and k cat /K m units should be ''min À1 '' and ''min À1 mM À1 ,'' respectively, rather than be ''s À1 '' and ''s À1 mM À1 .'' The scientific interpretations remain the same, only the units change. Our conclusions about the active site structure based on the kinetic analysis of the mutants do not change.

Sequence–Structure–Function Classification of a Catalytically Diverse Oxidoreductase Superfamily in Mycobacteria

“…To gain insight into the functional basis of this diversity, we expressed and purified 16 Fig. 2 & 3).…”

“…To gain more insight into the enzymes from the A1 sub-clusters, we compared the previously-solved crystal structures of rv3547 16 and MSMEG_3356 8 with a 1.5 Å resolution structure of MSMEG_2027 (Fig. 4A, Table S5).…”

“…4A), where the positions of the split β-barrel and substrate-binding helices are almost identical, despite less than 50% sequence identity. The key residues involved in F 420 stabilization including P52, W77 and N80 are structurally conserved, as are residues in the substrate binding pocket such as Y120 and Y126 which have been shown to be important for PA-824 activity in rv3547 16 (Fig. 4B&C).…”

“…A structural explanation for the non-overlapping PA-824 activity is evident in a comparison between the structures. MSMEG_3356 has a phenylalanine residue at position 123 in place of a tyrosine in rv3547; previous work has shown that this mutation knocked out PA-824 activity in rv3547 16 . Additionally, both MSMEG_2027 and MSMEG_3356 have methionine residues at position 54 in place of a tyrosine residue in rv3547; again, mutations at this position (Y65L and Y65A) completely knocked out PA-824 activity 16 .…”

“…MSMEG_3356 has a phenylalanine residue at position 123 in place of a tyrosine in rv3547; previous work has shown that this mutation knocked out PA-824 activity in rv3547 16 . Additionally, both MSMEG_2027 and MSMEG_3356 have methionine residues at position 54 in place of a tyrosine residue in rv3547; again, mutations at this position (Y65L and Y65A) completely knocked out PA-824 activity 16 . The significance of these tyrosine residues for catalytic activity with PA-824 is currently unclear, but it is possible that they are involved in stabilizing the nitro moiety that is not present in menadione.…”