Reference : Adenylate Kinase-Independent Thiamine Triphosphate Accumulation under Severe Energy S...
Scientific journals : Article
Life sciences : Biochemistry, biophysics & molecular biology
http://hdl.handle.net/2268/526
Adenylate Kinase-Independent Thiamine Triphosphate Accumulation under Severe Energy Stress in Escherichia Coli
English
Gigliobianco, Tiziana mailto [Université de Liège - ULg > > CNCM/ Centre fac. de rech. en neurobiologie cell. et moléc. >]
Lakaye, Bernard mailto [Université de Liège - ULg > Département des sciences biomédicales et précliniques > Biochimie et physiologie humaine et pathologique >]
Makarchikov, Alexander F [> > > >]
Wins, Pierre [> > > >]
Bettendorff, Lucien mailto [Université de Liège - ULg > Département des sciences biomédicales et précliniques > Biochimie et physiologie humaine et pathologique >]
2008
BMC Microbiology
8
16
Yes (verified by ORBi)
International
1471-2180
[en] BACKGROUND: Thiamine triphosphate (ThTP) exists in most organisms and might play a role in cellular stress responses. In E. coli, ThTP is accumulated in response to amino acid starvation but the mechanism of its synthesis is still a matter of controversy. It has been suggested that ThTP is synthesized by an ATP-dependent specific thiamine diphosphate kinase. However, it is also known that vertebrate adenylate kinase 1 catalyzes ThTP synthesis at a very low rate and it has been postulated that this enzyme is responsible for ThTP synthesis in vivo. RESULTS: Here we show that bacterial, as vertebrate adenylate kinases are able to catalyze ThTP synthesis, but at a rate more than 106-fold lower than ATP synthesis. This activity is too low to explain the high rate of ThTP accumulation observed in E. coli during amino acid starvation. Moreover, bacteria from the heat-sensitive CV2 strain accumulate high amounts of ThTP (>50% of total thiamine) at 37 degrees C despite complete inactivation of adenylate kinase and a subsequent drop in cellular ATP. CONCLUSION: These results clearly demonstrate that adenylate kinase is not responsible for ThTP synthesis in vivo. Furthermore, they show that E. coli accumulate large amounts of ThTP under severe energy stress when ATP levels are very low, an observation not in favor of an ATP-dependent mechanisms for ThTP synthesis.
http://hdl.handle.net/2268/526
10.1186/1471-2180-8-16
http://www.biomedcentral.com/1471-2180/8/16

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