ECF114

ECF subgroups

ECF114s1 221 ECF114s2 244 ECF114s3 98 ECF114s4 79 ECF114s5 39 ECF114s6 39 ECF114s7 45 ECF114s8 16 ECF114s9 10 ECF114s10 16 ECF114s11 22 ECF114s12 14

ECF proteins

General description: Members of ECF114 are homologous to members of original ECF114 (36.83%) and are present in Bacteroidetes (99.11%).

Genomic context conservation: The only conserved protein in the genomic context of members of ECF114 is a GDP-mannose 4,6 dehydratase (ECF114s6). One of the smallest subgroups of ECF114, ECF114s11, composed by only three proteins from representative organisms from the gut microbiota (Bacteroides uniformis ATCC 8492, Bacteroides thetaiotaomicron and Bacteroides stercoris ATC 43183), encodes proteins needed for carbohydrate catabolism (phosphoglycerate mutase, fructose-bisphosphate aldolase, 6-phosphofructokinase, methylglyoxal synthase) and anabolism (alpha-glucan phosphorylase), urea cycle (arginase), a Na⁺/H⁺ antiporter, a MarC-like protein of unknown function, a heat-shock protein and two copies of ferritin. Since iron can catalyze the synthesis of ROS in aerobic conditions, ferritin sequesters Fe²⁺ into an insoluble core as Fe³⁺, and releases it in a controlled manner (Orino et al., 2001). The two copies of ferritin in this region of the genome of B. uniformis and B. thetaiotaomicron are speculated to be required as iron storage to protect against ROS damage or/and as competitive advantage against other gastrointestinal bacteria (Rocha & Smith, 2013). Indeed, the expression of the ferritin in iron-replete media increases 10-fold in anaerobic media over aerobic culture (Rocha & Smith, 2013).

Studied members: SigH, from the oral cavity dweller Porphyromonas gingivalis, belongs to ECF114s4 and plays a role in aerotolerance (Yanamandra, Sarrafee, Anaya-Bergman, Jones, & Lewis, 2012). SigH is induced upon exposure to O_2, and its deletion mutant is downregulated in genes involved in oxidative stress protection (ferritin is the gene downregulated in a greater fold) and hemin uptake (Yanamandra et al., 2012).

Promoter motif conservation: Promoter motifs are not conserved, potentially due to the lack of autoregulation of members of ECF114 as it is the case for SigH from P. gingivalis (Yanamandra et al., 2012).

Summary: It is likely that ECF114 proteins play a role in aerotolerance of anaerobic Bacteroidetes and might participate in carbohydrate metabolism. We did not find any putative AS factor or potential modulator of members of ECF114, as in the case of original ECF114 (Staroń et al., 2009).