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Molecular characterization of CHAD domains as inorganic polyphosphate-binding modules

Published in Life Science Alliance. 2019, vol. 2, no. 3
Abstract Inorganic polyphosphates (polyPs) are linear polymers of orthophosphate units linked by phosphoanhydride bonds. Here, we report that bacterial, archaeal, and eukaryotic conserved histidine α-helical (CHAD) domains are specific polyP-binding modules. Crystal structures reveal that CHAD domains are formed by two four-helix bundles, giving rise to a central pore surrounded by conserved basic surface patches. Different CHAD domains bind polyPs with dissociation constants ranging from the nano- to mid-micromolar range, but not nucleic acids. A CHAD-polyP complex structure reveals the phosphate polymer binding across the central pore and along the two basic patches. Mutational analysis of CHAD-polyP interface residues validates the complex structure. The presence of a CHAD domain in the polyPase ygiF enhances its enzymatic activity. The only known CHAD protein from the plant Ricinus communis localizes to the nucleus/nucleolus when expressed in Arabidopsis and tobacco, suggesting that plants may harbor polyPs in these compartments. We propose that CHAD domains may be used to engineer the properties of polyP-metabolizing enzymes and to specifically localize polyP stores in eukaryotic cells and tissues.
PMID: 31133615
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Article (Published version) (3.9 MB) - public document Free access
Research group Groupe Hothorn
Autre: International Research Scholar Award from the Howard Hughes Medical Institute
European Commission: EUROPOLYPS
(ISO format)
LORENZO-ORTS, Laura et al. Molecular characterization of CHAD domains as inorganic polyphosphate-binding modules. In: Life Science Alliance, 2019, vol. 2, n° 3. doi: 10.26508/lsa.201900385 https://archive-ouverte.unige.ch/unige:121406

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Deposited on : 2019-07-30

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