Cell division in cocci: localization and properties of the Streptococcus pneumoniae FtsA protein.
We studied the cytological and biochemical properties of the FtsA protein of Streptococcus pneumoniae. FtsA is a widespread bacterial cell division protein that belongs to the actin superfamily. In Escherichia coli and Bacillus subtilis, FtsA localizes to the septal ring after FtsZ, but its exact role in septation is not known. In S. pneumoniae, we found that, during exponential growth, the protein localizes to the nascent septa, at the equatorial zones of the dividing cells, where an average of 2200 FtsA molecules per cell are present. Likewise, FtsZ was found to localize with the same pattern and to be present at an average of 3000 molecules per cell. Consistent with the colocalization, FtsA was found to interact with FtsZ and with itself. Purified FtsA is able to bind several nucleotides, the affinity being highest for adenosine triphosphate (ATP), and lower for other triphosphates and diphosphates. The protein polymerizes in vitro, in a nucleotide-dependent manner, forming long corkscrew-like helixes, composed of 2 + 2 paired protofilaments. No nucleotide hydrolytic activity was detected. Consistent with the absence of an ATPase activity, the polymers are highly stable and not dynamic. These results suggest that the FtsA protein could also polymerize in vivo and the polymers participate in septation.
Lara
Beatriz
B
Aventis Pharma, 102 Route de Noisy, F-93235 Romainville cedex, France.
Rico
Ana Isabel
AI
Petruzzelli
Sabrina
S
Santona
Antonella
A
Dumas
Jacques
J
Biton
Jacques
J
Vicente
Miguel
M
Mingorance
Jesús
J
Massidda
Orietta
O
D000255:Adenosine Triphosphate / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001704:Biopolymers / Q000378:metabolism*; D002455:Cell Division / Q000502:physiology*; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D020043:Genes, Essential; D008274:Magnesium / Q000378:metabolism; D016254:Mutagenesis, Insertional; D011994:Recombinant Proteins / Q000378:metabolism; D013296:Streptococcus pneumoniae / Q000166:cytology* / Q000235:genetics / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism; D020798:Two-Hybrid System Techniques
D001426:Bacterial Proteins; D001704:Biopolymers; D003598:Cytoskeletal Proteins; C065103:FtsA protein, Bacteria; C071525:FtsZ protein, Bacteria; D011994:Recombinant Proteins; D000255:Adenosine Triphosphate; D008274:Magnesium