The three-dimensional structure of septum site-determining protein MinD from Pyrococcus horikoshii OT3 in complex with Mg-ADP.
BACKGROUND
In Escherichia coli, the cell division site is determined by the cooperative activity of min operon products MinC, MinD, and MinE. MinC is a nonspecific inhibitor of the septum protein FtsZ, and MinE is the supressor of MinC. MinD plays a multifunctional role. It is a membrane-associated ATPase and is a septum site-determining factor through the activation and regulation of MinC and MinE. MinD is also known to undergo a rapid pole-to-pole oscillation movement in vivo as observed by fluorescent microscopy.


RESULTS
The three-dimensional structure of the MinD-2 from Pyrococcus horikoshii OT3 (PH0612) has been determined at 2.3 A resolution by X-ray crystallography using the Se-Met MAD method. The molecule consists of a beta sheet with 7 parallel and 1 antiparallel strands and 11 peripheral alpha helices. It contains the classical mononucleotide binding loop with bound ADP and magnesium ion, which is consistent with the suggested ATPase activity.


CONCLUSIONS
Structure analysis shows that MinD is most similar to nitrogenase iron protein, which is a member of the P loop-containing nucleotide triphosphate hydrolase superfamily of proteins. Unlike nitrogenase or other member proteins that normally work as a dimer, MinD was present as a monomer in the crystal. Both the 31P NMR and Malachite Green method exhibited relatively low levels of ATPase activity. These facts suggest that MinD may work as a molecular switch in the multiprotein complex in bacterial cell division.
Sakai
N
N
Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan.
Yao
M
M
Itou
H
H
Watanabe
N
N
Yumoto
F
F
Tanokura
M
M
Tanaka
I
I
D000244:Adenosine Diphosphate / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000378:metabolism*; D000595:Amino Acid Sequence; D001665:Binding Sites; D018360:Crystallography, X-Ray; D029968:Escherichia coli Proteins; D008274:Magnesium / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017510:Protein Folding; D017433:Protein Structure, Secondary; D019711:Pyrococcus / Q000201:enzymology*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D055672:Static Electricity
D029968:Escherichia coli Proteins; D000244:Adenosine Diphosphate; D000251:Adenosine Triphosphatases; C072069:MinD protein, E coli; D008274:Magnesium