6pbz
From Proteopedia
Crystal structure of Escherichia coli GppA
Structural highlights
Function[GPPA_ECOLI] Catalyzes the conversion of pppGpp to ppGpp. Guanosine pentaphosphate (pppGpp) is a cytoplasmic signaling molecule which together with ppGpp controls the 'stringent response', an adaptive process that allows bacteria to respond to amino acid starvation, resulting in the coordinated regulation of numerous cellular activities (PubMed:6130093, PubMed:8394006). In vitro, can hydrolyze pppGp (PubMed:6130093). Also has exopolyphosphatase activity, catalyzing the release of orthophosphate by processive hydrolysis of the phosphoanyhydride bonds of polyphosphate chains (1000 residues) (PubMed:8394006).[1] [2] Publication Abstract from PubMedRapid adaptation to environmental changes is crucial for bacterial survival. Almost all bacteria possess a conserved stringent response system to prompt transcriptional and metabolic responses toward stress. The adaptive process relies on alarmones, guanosine pentaphosphate (pppGpp) and tetraphosphate (ppGpp), to regulate global gene expression. The ppGpp is more potent than pppGpp in the regulatory activity and pppGpp phosphohydrolase (GppA) plays a key role in (p)ppGpp homeostasis. Sharing a similar domain structure, GppA is indistinguishable from exopolyphosphatase (PPX), which mediates the metabolism of cellular inorganic polyphosphate. Here, our phylogenetic analysis of PPX/GppA homologs in bacteria shows a wide distribution with several distinct subfamilies, and our structural and functional analysis of Escherichia coli GppA and Helicobacter pylori PPX/GppA reveals unique properties of each homolog. These results explain how each homolog possesses its distinct functionality. Structure and Activity of PPX/GppA Homologs from Escherichia coli and Helicobacter pylori.,Song H, Dharmasena MN, Wang C, Shaw GX, Cherry S, Tropea JE, Jin DJ, Ji X FEBS J. 2019 Nov 2. doi: 10.1111/febs.15120. PMID:31679177[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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Categories: Ecoli | Guanosine-5'-triphosphate,3'-diphosphate diphosphatase | Large Structures | Ji, X | Shaw, G X | Song, H | Wang, C | Gppa | Hydrolase | Ppgpp | Pppgpp | Ppx
