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Review article

https://doi.org/10.5562/cca2116

Still a Long Way to Fully Understanding the Molecular Mechanism of Escherichia coli Purine Nucleoside Phosphorylase

Zoran Štefanić ; Division of Physical Chemistry, Ruđer Bošković Institute, P.O. Box 180, HR-10002 Zagreb, Croatia
Goran Mikleušević ; Division of Physical Chemistry, Ruđer Bošković Institute, P.O. Box 180, HR-10002 Zagreb, Croatia
Marta Narczyk ; Division of Biophysics, Institute of Experimental Physics, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
Beata Wielgus-Kutrowska ; Division of Biophysics, Institute of Experimental Physics, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
Agnieszka Bzowska ; Division of Biophysics, Institute of Experimental Physics, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
Marija Luić ; Division of Physical Chemistry, Ruđer Bošković Institute, P.O. Box 180, HR-10002 Zagreb, Croatia


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Abstract

The results of several decades of studying the catalytic mechanism of Escherichia coli purine
nucleoside phosphorylases (PNP) by solution studies and crystal structure determinations are presented.
Potentially PNPs can be used for enzyme-activating prodrug gene therapy against solid tumours because
of the differences in specificity between human and E. coli PNPs. Biologically active form of PNP from
E. coli is a homohexamer that catalyses the phosphorolytic cleavage of the glycosidic bond of purine nucleosides.
Two conformations of the active site are possible after substrate(s) binding: open and closed. A
series of determined 3D-structures of PNP binary and ternary complexes facilitated the prediction of the
main steps in the catalytic mechanism. For their validation the active site mutants: Arg24Ala, Asp204Ala,
Arg217Ala, Asp204Asn and double mutant Asp204Ala/Arg217Ala were prepared. The activity tests confirm
that catalysis involves protonation of the purine base at position N7 and give better insight into the
cooperativity between subunits in this oligomeric enzyme. (doi: 10.5562/cca2116)

Keywords

purine nucleoside phosphorylase, catalysis, cooperativity

Hrčak ID:

101919

URI

https://hrcak.srce.hr/101919

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