scholarly journals Influence of Cluster Formation of Acidic Phospholipids on Decrease in the Affinity for ATP of DnaA Protein

1996 ◽  
Vol 271 (7) ◽  
pp. 3633-3638 ◽  
Author(s):  
Tohru Mizushima ◽  
Yuichi Ishikawa ◽  
Eishi Obana ◽  
Masakazu Hase ◽  
Toshio Kubota ◽  
...  
2000 ◽  
Vol 182 (9) ◽  
pp. 2604-2610 ◽  
Author(s):  
Gillian Newman ◽  
Elliott Crooke

ABSTRACT Given the lack of a nucleus in prokaryotic cells, the significance of spatial organization in bacterial chromosome replication is only beginning to be fully appreciated. DnaA protein, the initiator of chromosomal replication in Escherichia coli, is purified as a soluble protein, and in vitro it efficiently initiates replication of minichromosomes in membrane-free DNA synthesis reactions. However, its conversion from a replicatively inactive to an active form in vitro occurs through its association with acidic phospholipids in a lipid bilayer. To determine whether the in situ residence of DnaA protein is cytoplasmic, membrane associated, or both, we examined the cellular location of DnaA using immunogold cryothin-section electron microscopy and immunofluorescence. Both of these methods revealed that DnaA is localized at the cell membrane, further suggesting that initiation of chromosomal replication in E. coli is a membrane-affiliated event.


2000 ◽  
Vol 276 (10) ◽  
pp. 7450-7456 ◽  
Author(s):  
Masaki Makise ◽  
Shinji Mima ◽  
Tomofusa Tsuchiya ◽  
Tohru Mizushima

2002 ◽  
Vol 363 (2) ◽  
pp. 305 ◽  
Author(s):  
Kohji YAMAMOTO ◽  
Syed MUNIRUZZAMAN ◽  
Malini RAJAGOPALAN ◽  
Murty V. V. S. MADIRAJU

1999 ◽  
Vol 340 (2) ◽  
pp. 433 ◽  
Author(s):  
Yoshihiro YAMAGUCHI ◽  
Masakazu HASE ◽  
Masaki MAKISE ◽  
Shinji MIMA ◽  
Takeshi YOSHIMI ◽  
...  

2000 ◽  
Vol 275 (6) ◽  
pp. 4513-4518 ◽  
Author(s):  
Masaki Makise ◽  
Shinji Mima ◽  
Tomofusa Tsuchiya ◽  
Tohru Mizushima

2002 ◽  
Vol 362 (2) ◽  
pp. 453-458 ◽  
Author(s):  
Masaki MAKISE ◽  
Shinji MIMA ◽  
Motohiro KOTERASAWA ◽  
Tomofusa TSUCHIYA ◽  
Tohru MIZUSHIMA

The DnaA protein is the initiator of chromosomal DNA replication in Escherichia coli. Acidic phospholipids decrease its affinity for adenine nucleotides, and re-activate the ADP-bound form to the ATP-bound form. We have previously reported that two mutant forms, DnaAR328E and DnaAK372E, have decreased affinity for cardiolipin (CL). In the present study, we constructed a mutant DnaA protein, DnaA435, with both R328E and K372E, and compared its biochemical characteristics with those of DnaAR328E and DnaAK372E. DnaA435 could bind to oriC DNA, but did not bind ATP or ADP. In DnaA435, compared with DnaAR328E and DnaAK372E, CL caused less inhibition of oriC DNA binding, suggesting that amino acids R328 and K372 are involved in the interaction of DnaA with acidic phospholipids. DnaA435 could initiate DNA synthesis on oriC both in vivo and in vitro. Based on these results, we propose that ATP activates DnaA protein by changing its higher order structure around R328 and K372.


2002 ◽  
Vol 363 (2) ◽  
pp. 305-311
Author(s):  
Kohji YAMAMOTO ◽  
Syed MUNIRUZZAMAN ◽  
Malini RAJAGOPALAN ◽  
Murty V.V.S. MADIRAJU

The biochemical aspects of the initiation of DNA replication in Mycobacterium tuberculosis are unknown. To understand this process, we overproduced, purified and characterized the recombinant M. tuberculosis DnaA protein. The M. tuberculosis DnaA protein binds the origin of replication (oriC), ATP and ADP, and exhibited weak ATPase activity. ADP, after hydrolysis of ATP, remained strongly associated with DnaA and the exchange of ATP for bound ADP was weak. Vesicles prepared from acidic phospholipids, such as phosphatidylinositol, cardiolipin and phosphatidylglycerol, promoted dissociation of both ADP and ATP, whereas the neutral phospholipid phosphatidylethanolamine did not. The phospholipid-mediated dissociation of ATP was decreased in the presence of the M. tuberculosis oriC, whereas dissociation of ADP was stimulated in the presence of oriC. Acidic phospholipids in micelles, however, were not efficient in dissociating bound nucleotides from DnaA. Together, these results suggest that both polar head groups and membrane bilayer structure play an important role in M. tuberculosis DnaA—adenine-nucleotide interactions. We suggest that initiation of M. tuberculosis oriC involves intimate interactions between DnaA, adenine nucleotides and membrane phospholipids, and the latter helps to ensure that only the ATP form of the DnaA protein interacts continuously with oriC.


1999 ◽  
Vol 340 (2) ◽  
pp. 433-438 ◽  
Author(s):  
Yoshihiro YAMAGUCHI ◽  
Masakazu HASE ◽  
Masaki MAKISE ◽  
Shinji MIMA ◽  
Takeshi YOSHIMI ◽  
...  

We reported previously that three basic amino acids (Arg-360, Arg-364 and Lys-372) of DnaA protein are essential for its functional interaction with cardiolipin. In this study, we examined the effect of mutation of some basic amino acids in a potential amphipathic helix (from Lys-327 to Ile-345) of DnaA protein on this interaction. ATP binding to the mutant DnaA protein, in which Arg-328, Arg-334 and Arg-342 were changed to acidic amino acids, was less inhibited by cardiolipin than that of the wild-type protein, as was the case for mutant DnaA protein with mutations of Arg-360, Arg-364 and Lys-372. A mutant DnaA protein with mutations of all six basic amino acids showed the most resistance to the inhibition of ATP binding by cardiolipin. These results suggest that Arg-328, Arg-334 and Arg-342, like Arg-360, Arg-364 and Lys-372, are also involved in the functional interaction between DnaA protein and acidic phospholipids.


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