5u05

Cryo-EM structure of the E. coli CTP synthase tetramer

Loading... Status: waiting for Mol* initialization Structural highlights 5u05 is a 4 chain structure with sequence from "bacillus_coli"_migula_1895 "bacillus coli" migula 1895. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Related: 5u03 Gene: pyrG, ECS88_3048 ("Bacillus coli" Migula 1895) Activity: CTP synthase (glutamine hydrolyzing), with EC number 6.3.4.2 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [PYRG_ECO45] Catalyzes the ATP-dependent amination of UTP to CTP with either L-glutamine or ammonia as the source of nitrogen. Regulates intracellular CTP levels through interactions with the four ribonucleotide triphosphates. Publication Abstract from PubMed The universally conserved enzyme CTP synthase (CTPS) forms filaments in bacteria and eukaryotes. In bacteria, polymerization inhibits CTPS activity and is required for nucleotide homeostasis. Here we show that for human CTPS, polymerization increases catalytic activity. The cryo-EM structures of bacterial and human CTPS filaments differ considerably in overall architecture and in the conformation of the CTPS protomer, explaining the divergent consequences of polymerization on activity. The structure of human CTPS filament, the first structure of the full-length human enzyme, reveals a novel active conformation. The filament structures elucidate allosteric mechanisms of assembly and regulation that rely on a conserved conformational equilibrium. The findings may provide a mechanism for increasing human CTPS activity in response to metabolic state and challenge the assumption that metabolic filaments are generally storage forms of inactive enzymes. Allosteric regulation of CTPS polymerization by ligands likely represents a fundamental mechanism underlying assembly of other metabolic filaments. Human CTP synthase filament structure reveals the active enzyme conformation.,Lynch EM, Hicks DR, Shepherd M, Endrizzi JA, Maker A, Hansen JM, Barry RM, Gitai Z, Baldwin EP, Kollman JM Nat Struct Mol Biol. 2017 May 1. doi: 10.1038/nsmb.3407. PMID:28459447 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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