fldA is an essential gene required in the 2‐C‐methyl‐D‐erythritol 4‐phosphate pathway for isoprenoid biosynthesis

Abstract

Although flavodoxin I is indispensable for Escherichia coli growth, the exact pathway(s) where flavodoxin I is essential has not been identified. We performed transposon mutagenesis of the flavodoxin I gene, fldA, in an E. coli strain that expressed mevalonate pathway enzymes and that had a point mutation in the lytB gene of the MEP pathway resulting in the accumulation of (E)-4-hydroxy-3-methylbutyl-2-enyl pyrophosphate (HMBPP). Disruption of fldA abrogated mevalonate-independent growth and dramatically decreased HMBPP levels. The fldA À mutant grew with mevalonate indicating that the essential role of flavodoxin I under aerobic conditions is in the MEP pathway. Growth was restored by fldA complementation. Since GcpE (which synthesizes HMBPP) and LytB are iron-sulfur enzymes that require a reducing system for their activity, we propose that flavodoxin is essential for GcpE and possibly LytB activity. Thus, the essential role for flavodoxin I in E. coli is in the MEP pathway for isoprenoid biosynthesis.

Escherichia coli transcription factor YncC (McbR) regulates colanic acid and biofilm formation by repressing expression of periplasmic protein YbiM (McbA)

“…sixA was induced 4.0-fold and encodes a signal inhibitory factor-X (Ogino et al, 1998) that was induced in E. coli TG1 and TG biofilms (Beloin et al, 2004). fldA was induced 5.3-fold and encodes flavodoxin 1 (Puan et al, 2005) that was induced in the human urine biofilms of the asymptomatic E. coli bacteriuria strains (Hancock and Klemm, 2007).…”

Isoprenoid biosynthesis in bacterial pathogens

“…MEP pathway branched from the lytB gene. The study by Puan et al (2005) proposed that the flavodoxin I gene (fldA) (a gene known to be essential in E. coli) has a role in the MEP pathway by providing the reducing system required for the enzymic activation of GcpE and LytB. Whilst much of the genetic characterization has been performed using laboratory strains of E. coli, it is clear that pathogenic E. coli strains (including enterohaemorrhagic, enteroaggregative, enterotoxigenic, enteroinvasive and enteropathogenic strains) also possess the MEP pathway and lack genes encoding enzymes of the mevalonate pathway (Table 1).…”

Solution Structures and Backbone Dynamics of a Flavodoxin MioC from Escherichia coli in both Apo- and Holo-forms

“…Furthermore, the three FMN-binding loops and the 120s loop are highly mobile and adopt a flexible conformation, in accordance with the lack of NOE contacts and high internal flexibility (see below). The holo-form of MioC also contains four ␣-helices (residues Gly 14 41 to Asp 43 form a short 3 10 helix (HЈ). The core structure is similar to that of the apo-form, but the secondary structures are significantly extended and stabilized.…”

“…as pyruvate-formate lyase (13) and (E)-4-hydroxy-3-methylbutyl-2-enyl pyrophosphate synthase (14). It has been established by potentiometry that electrons flow from NADPH to flavodoxin reductase and then to flavodoxin, which subsequently transfers the electron to the downstream targets (15).…”