Mihaela-Carmen Unciuleac is a joint first author of a 2021 study connecting polynucleotide phosphorylase structure with its reversible reactions at an RNA chain's end. In one direction, phosphorolysis releases nucleoside diphosphates; in the other, those substrates supply units for extension.[ref]
The study combined cryo-electron microscopy with changes to selected amino acid residues and measurements of enzyme activity. The structure localized substrate and metal-binding features; the activity comparisons tested their functional importance.[ref]
Structure and mechanism of Mycobacterium smegmatis polynucleotide phosphorylase by Mihaela-Carmen Unciuleac and others. Abstract and Results, structure-guided mutational analysis
For an original accounting example, shortening an RNA from 12 to eight nucleotides through four terminal phosphorolysis events consumes four inorganic phosphate equivalents and releases four nucleoside diphosphates. Reversing those four events consumes four nucleoside diphosphates and releases four phosphate equivalents. This balances the two directions without assuming that a reaction mixture must run equally fast both ways.
A structural contact also differs from a demonstrated chemical requirement. In the paper's Figure4, an imported comparison phosphate helps interpret the active site; it is not a directly resolved phosphate from that same reconstruction.[ref]
Structure and mechanism of Mycobacterium smegmatis polynucleotide phosphorylase by Mihaela-Carmen Unciuleac and others. Figure4, observed RNA/metals distinguished from the comparison phosphate
Comparing structural placement with separate reaction measurements makes the mechanistic claim testable without assigning unreported individual tasks to an author. Articles by others on the same topic
There are currently no matching articles.