PDBsum entry 5u05

Ligase

PDB id: 5u05

Contents

Protein chains

534 a.a.

PDB id:

5u05

Name:

Ligase

Title:

Cryo-em structure of the e. Coli ctp synthase tetramer

Structure:

Ctp synthase. Chain: a, b, c, d. Synonym: cytidine 5'-triphosphate synthase, cytidine triphosphate synthetase, ctps, utp--ammonia ligase. Engineered: yes

Source:

Escherichia coli. Organism_taxid: 562. Gene: pyrg, ecs88_3048. Expressed in: escherichia coli. Expression_system_taxid: 562

Authors:

E.M.Lynch,D.R.Hicks,J.M.Kollman

Key ref:

E.M.Lynch et al. (2017). Human CTP synthase filament structure reveals the active enzyme conformation. Nat Struct Mol Biol, 24, 507-514. PubMed id: 28459447

Date:

22-Nov-16 Release date: 26-Apr-17

Protein chains

P0A7E5  (PYRG_ECOLI) -  CTP synthase from Escherichia coli (strain K12)

Seq: 545 a.a.

Struc: 534 a.a.

Enzyme reactions

• Enzyme class: E.C.6.3.4.2 - Ctp synthase (glutamine hydrolyzing).
• Reaction: UTP + L-glutamine + ATP + H2O = CTP + L-glutamate + ADP + phosphate + 2 H⁺

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

Nat Struct Mol Biol 24:507-514 (2017)

PubMed id: 28459447

Human CTP synthase filament structure reveals the active enzyme conformation.

E.M.Lynch, D.R.Hicks, M.Shepherd, J.A.Endrizzi, A.Maker, J.M.Hansen, R.M.Barry, Z.Gitai, E.P.Baldwin, J.M.Kollman.

ABSTRACT

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.