Deletion of a mycobacterial gene encoding a reductase leads to an altered cell wall containing β-oxo-mycolic acid analogues, and the accumulation of long-chain ketones related to mycolic acids

1    121140 and 1.23e-02, respectively) strongly suggested that 1cyd (Mus musculus carbonyl

2   reductase complexed with NADPH and 2-propanol) was the closest match to Rv2709 (22%

3   sequence identity). Using the 1cyd co-ordinates and the FUGUE server (Shi et al., 2001) we

4   generated an in silico 3D structure of Rv2509. The predictions revealed similar 3D structural

5   folds for 1cyd, Rv2509 and the E. coli fatty acid reductase, FabG (data not shown).

6 Additionally, when the NADPH moiety from 1cyd was superimposed in the predicted NADP-
7 binding fold of Rv2509, the predicted distances between the conserved residues and the co-
8 factor showed a fit similar to that seen in 1cyd (data not shown). These data suggested that
9   Rv2509 was likely a NAD/NADP-dependent mycobacterial reductase. As outlined above, the

10 homologous M. smegmatis gene MSMEG4722 was chosen for further analysis.

11
12 Deletion of MSMEG4722 in M. smegmatis mc²155 alters culture characteristics and
13 sensitivity to antibiotics

14   To study the role of MSMEG4722 in mycolic acid motif formation, we deleted MSMEG4722 in

15   M. smegmatis mc²155 by specialized transduction (Bardarov et al., 2002) (Figure 2A). The

16   ability to generate a null mutant indicated that MSMEG4722 was not essential for the viability of

17   M. smegmatis mc²155. Loss of MSMEG4722 had a remarkable effect of the colony morphology

18   of M. smegmatis mc²155 on TSB agar. While the colonies of the parental, wild type strain

19   mc²155 were glossy, those of the mutant strain ∆MSMEG4722 appeared to have a dry surface

20   (Figure 2B). The change was more apparent when the strains were grown on TSB agar

21   supplemented with Tween-80. Unlike colonies of the parental strain mc²155 which had a

22   smooth surface, colonies of ∆MSMEG4722 had an irregular, convoluted surface (Figure 2B).

<<   2   3   4   5   6   7   8   >>

More intriguing information