Functional analysis of the cytoskeleton protein MreB from Chlamydophila pneumoniae.
In rod-shaped bacteria, the bacterial actin ortholog MreB is considered to organize the incorporation of cell wall precursors into the side-wall, whereas the tubulin homologue FtsZ is known to tether incorporation of cell wall building blocks at the developing septum. For intracellular bacteria, there is no need to compensate osmotic pressure by means of a cell wall, and peptidoglycan has not been reliably detected in Chlamydiaceae. Surprisingly, a nearly complete pathway for the biosynthesis of the cell wall building block lipid II has been found in the genomes of Chlamydiaceae. In a previous study, we discussed the hypothesis that conservation of lipid II biosynthesis in cell wall-lacking bacteria may reflect the intimate molecular linkage of cell wall biosynthesis and cell division and thus an essential role of the precursor in cell division. Here, we investigate why spherical-shaped chlamydiae harbor MreB which is almost exclusively found in elongated bacteria (i.e. rods, vibrios, spirilla) whereas they lack the otherwise essential division protein FtsZ. We demonstrate that chlamydial MreB polymerizes in vitro and that polymerization is not inhibited by the blocking agent A22. As observed for MreB from Bacillus subtilis, chlamydial MreB does not require ATP for polymerization but is capable of ATP hydrolysis in phosphate release assays. Co-pelleting and bacterial two-hybrid experiments indicate that MreB from Chlamydophila (Chlamydia) pneumoniae interacts with MurF, MraY and MurG, three key components in lipid II biosynthesis. In addition, MreB polymerization is improved in the presence of MurF. Our findings suggest that MreB is involved in tethering biosynthesis of lipid II and as such may be necessary for maintaining a functional divisome machinery in Chlamydiaceae.
University of Bonn, Institute for Medical Microbiology, Immunology and Parasitology, Pharmaceutical Microbiology Section, Bonn, Germany.
Ahmed
A
Gaballah
Anna
A
Kloeckner
Christian
C
Otten
Hans-Georg
HG
Sahl
Beate
B
Henrichfreise
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000494:pharmacology; D001426:Bacterial Proteins / Q000378:metabolism*; D016993:Chlamydophila pneumoniae / Q000187:drug effects / Q000378:metabolism*; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D006868:Hydrolysis / Q000187:drug effects; D008954:Models, Biological; D050505:Mutant Proteins / Q000378:metabolism; D058105:Polymerization / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D013890:Thiourea / Q000031:analogs & derivatives / Q000494:pharmacology; D020798:Two-Hybrid System Techniques; D014538:Uridine Diphosphate N-Acetylmuramic Acid / Q000031:analogs & derivatives / Q000096:biosynthesis
D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; D050505:Mutant Proteins; D014538:Uridine Diphosphate N-Acetylmuramic Acid; C069249:muramyl-NAc-(pentapeptide)pyrophosphoryl-undecaprenol; C015799:2,6-dichlorobenzylthiopseudourea; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D013890:Thiourea