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Enterococcus faecalis FIC protein in complex with AMP and calcium ion.Enterococcus faecalis FIC protein in complex with AMP and calcium ion.
Structural highlights
Publication Abstract from PubMedFIC proteins regulate molecular processes from bacteria to humans by catalyzing post-translational modifications (PTM), the most frequent being the addition of AMP or AMPylation. In many AMPylating FIC proteins, a structurally conserved glutamate represses AMPylation and, in mammalian FICD, also supports deAMPylation of BiP/GRP78, a key chaperone of the unfolded protein response. Currently, a direct signal regulating these FIC proteins has not been identified. Here, we use X-ray crystallography and in vitro PTM assays to address this question. We discover that Enterococcus faecalis FIC (EfFIC) catalyzes both AMPylation and deAMPylation and that the glutamate implements a multi-position metal switch whereby Mg(2+) and Ca(2+) control AMPylation and deAMPylation differentially without a conformational change. Remarkably, Ca(2+) concentration also tunes deAMPylation of BiP by human FICD. Our results suggest that the conserved glutamate is a signature of AMPylation/deAMPylation FIC bifunctionality and identify metal ions as diffusible signals that regulate such FIC proteins directly. A Ca(2+)-regulated deAMPylation switch in human and bacterial FIC proteins.,Veyron S, Oliva G, Rolando M, Buchrieser C, Peyroche G, Cherfils J Nat Commun. 2019 Mar 8;10(1):1142. doi: 10.1038/s41467-019-09023-1. PMID:30850593[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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