Pyrroloquinoline-quinone synthesized in Escherichia coli by pyrroloquinoline-quinone synthase of Deinococcus radiodurans plays a role beyond mineral phosphate solubilization.
Deinococcus radiodurans, an extremely radioresistant bacterium, synthesizes coenzyme pyrroloquinoline-quinone (PQQ) but exhibits a negative phenotype for mineral phosphate solubilization. Gene for the putative PQQ synthesizing protein was PCR amplified and cloned from Deinococcus, sequenced, and expressed in Escherichia coli, under an inducible E. coli promoter. The transgenic E. coli expressed PQQ synthase protein of 42kDa and complemented the mineral phosphate solubilization phenotype of E. coli, suggesting the synthesis of an active protein. The cells expressing high levels of this protein showed increased protection against photodynamically produced reactive oxygen species. The effect could be attributed to the upregulation of antioxidant enzymes such as catalase and superoxide dismutase by PQQ in transgenic E. coli through an unknown mechanism. The study elucidates a hitherto unknown possible function of PQQ in bacteria.
Khairnar
Nivedita P
NP
Molecular Biology Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.
Misra
Hari S
HS
Apte
Shree K
SK
D000975:Antioxidants / Q000378:metabolism; D002130:Calcium Phosphates / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects / Q000528:radiation effects; D003067:Coenzymes / Q000235:genetics / Q000378:metabolism; D034301:Deinococcus / Q000201:enzymology* / Q000235:genetics; D004789:Enzyme Activation; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development* / Q000528:radiation effects; D008903:Minerals / Q000378:metabolism; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism*; D045542:PQQ Cofactor / Q000235:genetics / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism; D011836:Radiation Tolerance / Q000187:drug effects / Q000502:physiology; D017382:Reactive Oxygen Species / Q000378:metabolism; D011994:Recombinant Proteins; D012395:Rose Bengal / Q000494:pharmacology; D012995:Solubility
D000975:Antioxidants; D002130:Calcium Phosphates; D003067:Coenzymes; D008903:Minerals; D009097:Multienzyme Complexes; D010710:Phosphates; D017382:Reactive Oxygen Species; D011994:Recombinant Proteins; C485817:beta-tricalcium phosphate; C076608:pyrroloquinoline quinone synthase complex; D012395:Rose Bengal; D045542:PQQ Cofactor; C018392:tricalcium phosphate