Global Functional Atlas of Escherichia coli Encompassing Previously Uncharacterized Proteins
Figure 7
Evolutionary Conservation of Orphan Protein Function
(A) Evolutionary conservation of orphan and annotated E. coli protein interaction partners in the integrated PI-GC network based on the co-occurrence of putative orthologs across fully sequenced prokaryotic genomes.
(B) Phylogenetic distribution of the components of 97 functional neighborhoods with at least one orphan; the proportion of genomes showing conservation is indicated.
(C) Atypical neighborhood illustrating broader conservation of orphans than annotated components; node shading reflects average phylogenetic conservation.
(D) Representative neighborhood involved in drug efflux exhibiting similar phylogenetic distributions among its orphan and annotated components; analogous neighborhoods shown in preceding figures are indicated below [B].
(E) Serial-dilution assay showing the drug hypersensitivity of deletion mutants of the orphans listed in [D].
(F) DNA-replication neighborhood exhibiting a tendency of annotated components to be more widely distributed than the orphans.
(G) Serial-dilution assay showing the perturbed growth of strains deleted for the two orphan components shown in [F] in the presence of an antibiotic inhibitor of DNA-replication; an asterisk (*) indicates hypomorphic alleles. Mutants deleted of relevant annotated proteins are shown as positive controls, while mutants lacking genes not contained within this neighborhood are shown as negative controls. LB, Luria Bertani medium.