Phage-display and correlated mutations identify an essential region of subdomain 1C involved in homodimerization of Escherichia coli FtsA.
FtsA plays an essential role in Escherichia coli cell division and is nearly ubiquitous in eubacteria. Several evidences postulated the ability of FtsA to interact with other septation proteins and with itself. To investigate these binding properties, we screened a phage-display library with FtsA. The isolated peptides defined a degenerate consensus sequence, which in turn displayed a striking similarity with residues 126-133 of FtsA itself. This result suggested that residues 126-133 were involved in homodimerization of FtsA. The hypothesis was supported by the analysis of correlated mutations, which identified a mutual relationship between a group of amino acids encompassing the ATP-binding site and a set of residues immediately downstream to amino acids 126-133. This information was used to assemble a model of a FtsA homodimer, whose accuracy was confirmed by probing multiple alternative docking solutions. Moreover, a prediction of residues responsible for protein-protein interaction validated the proposed model and confirmed once more the importance of residues 126-133 for homodimerization. To functionally characterize this region, we introduced a deletion in ftsA, where residues 126-133 were skipped. This mutant failed to complement conditional lethal alleles of ftsA, demonstrating that amino acids 126-133 play an essential role in E. coli.
Carettoni
Daniele
D
GlaxoSmithKline Medicines Research Center, Via Fleming 4, 37135 Verona, Italy. daniele.carettoni.dc@axxam.com
Gómez-Puertas
Paulino
P
Yim
Lucía
L
Mingorance
Jesús
J
Massidda
Orietta
O
Vicente
Miguel
M
Valencia
Alfonso
A
Domenici
Enrico
E
Anderluzzi
Daniela
D
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001435:Bacteriophages / Q000235:genetics*; D001483:Base Sequence; D019281:Dimerization; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D019151:Peptide Library; D010455:Peptides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C065103:FtsA protein, Bacteria; C489310:FtsA protein, E coli; D019151:Peptide Library; D010455:Peptides