Poly-(R)-3-hydroxybutyrate and the pioneering work of Rosetta Natoli Reusch.

In investigating genetic competence, Reusch and collaborators have found that the concentration of short chain poly-(R)-3-hydroxybutyrate (PHB) and polyphosphate (polyP) complexes increases with genetic transformability and that interrupting DNA uptake yields single-stranded donor DNA complexed with short chain PHB. This would be consistent with the organic polyphosphate, DNA, replacing the inorganic polyphosphate, polyP, in the PHB pore so allowing the DNA to be drawn into the cell. Reusch has gone on to show that PHB and polyphosphate, extracted from membranes or synthesized chemically, together form a voltage-activated calcium-selective channel. One may wonder whether the classical proteinaceous calcium channels have a short chain PHB/polyP core--and whether other ion channels have this core too. It is therefore significant that in Streptomyces lividans the potassium channel KcsA, which resembles that of eukaryotes, forms tetramers that contain polyP whilst both monomers and tetramers are covalently linked to short chain PHB. Pumps are the counterparts of channels. Reusch has also shown that a model pump, the calcium ATPase pump of human erythrocytes, contains both cPHB and polyP and has strongly implicated these polymers in its functioning. Again, one may wonder whether these polymers are essential constituents of other pumps. Reusch has gone on to show that a wide range of proteins are modified post-translationally by covalent addition of short chain PHB in both prokaryotes and eukaryotes including DNA-binding proteins such as histones. Finally, Reusch has extended the importance of short chain PHB to medicine by showing its likely involvement in atherogenic plaques and diabetes. And yet this opus has gone largely unnoticed.