Structural and Biochemical Analysis of a Phosin from Streptomyces chartreusis Reveals a Combined Polyphosphate- and Metal-Binding Fold

Sebastiaan Werten (1) , Nils Hinnerk Rustmeier (2) , Maximilian Gemmer (2) , Marie-Joëlle Virolle (3, 4) , Winfried Hinrichs (2)

1 Biocenter - Division of Biological Chemistry [Innsbruck, Austria]
2 Institute for Biochemistry - Department of Molecular Structural Biology [Greifswald, Germany]
3 I2BC - Institut de Biologie Intégrative de la Cellule
4 MESMIC - Métabolisme Energétique des Streptomyces

X-ray crystallographic analysis of a phosin (PptA) from Steptomyces chartreusis reveals a metal-associated, lozenge-shaped fold featuring a 5–10 angström wide, positively charged tunnel that traverses the protein core. Two distinct metal-binding sites were identified in which the predominant metal ion was Cu2+. In solution, PptA forms stable homodimers that bind with nanomolar affinity to polyphosphate, a stress-related biopolymer acting as a phosphate and energy reserve in conditions of nutrient depletion. A single protein dimer interacts with 14–15 consecutive phosphate moieties within the polymer. Our observations suggest that PptA plays a role in polyphosphate metabolism, mobilisation or sensing, possibly by acting in concert with polyphosphate kinase (Ppk). Like Ppk, phosins may influence antibiotic synthesis by streptomycetes.

Mots clés: secondary metabolism; signalling; Conserved histidine α-helical domain (CHAD); nutritional stress; phosphate metabolism; antibiotics; conserved histidine a-helical domain; polyP; polyphosphate

Domaines: Sciences du Vivant [q-bio]

Sebastiaan Werten, Nils Hinnerk Rustmeier, Maximilian Gemmer, Marie-Joëlle Virolle, Winfried Hinrichs. Structural and Biochemical Analysis of a Phosin from Streptomyces chartreusis Reveals a Combined Polyphosphate- and Metal-Binding Fold. FEBS Letters, 2019, Epub ahead of print. ⟨10.1002/1873-3468.13476⟩. ⟨hal-02174917⟩