PDBsum entry 1z7m

Transferase

PDB id: 1z7m

Contents

Protein chains

311 a.a. *

200 a.a. *

201 a.a. *

Ligands

WO4 ×2

PO4 ×6

* Residue conservation analysis

PDB id:

1z7m

Name:

Transferase

Title:

Atp phosphoribosyl transferase (hiszg atp-prtase) from lactococcus lactis

Structure:

Atp phosphoribosyltransferase regulatory subunit. Chain: a, b, c, d. Engineered: yes. Atp phosphoribosyltransferase. Chain: e, f, g, h. Synonym: atp-prtase, atp-prt. Engineered: yes

Source:

Lactococcus lactis. Organism_taxid: 1358. Gene: hisz. Expressed in: escherichia coli. Expression_system_taxid: 562. Gene: hisg.

Biol. unit:

Octamer (from PQS)

Resolution:

2.90Å R-factor: 0.245 R-free: 0.286

Authors:

K.S.Champagne,M.Sissler,Y.Larrabee,S.Doublie,C.S.Francklyn

Key ref:

K.S.Champagne et al. (2005). Activation of the hetero-octameric ATP phosphoribosyl transferase through subunit interface rearrangement by a tRNA synthetase paralog. J Biol Chem, 280, 34096-34104. PubMed id: 16051603 DOI: 10.1074/jbc.M505041200

Date:

25-Mar-05 Release date: 09-Aug-05

Protein chains

Q02147  (HISZ_LACLA) -  ATP phosphoribosyltransferase regulatory subunit from Lactococcus lactis subsp. lactis (strain IL1403)

Seq: 328 a.a.

Struc: 311 a.a.

Protein chains

Q02129  (HIS1_LACLA) -  ATP phosphoribosyltransferase from Lactococcus lactis subsp. lactis (strain IL1403)

Seq: 208 a.a.

Struc: 200 a.a.

Protein chains

Q02129  (HIS1_LACLA) -  ATP phosphoribosyltransferase from Lactococcus lactis subsp. lactis (strain IL1403)

Seq: 208 a.a.

Struc: 201 a.a.

Enzyme reactions

• Enzyme class 2: Chains A, B, C, D: E.C.?
• Enzyme class 3: Chains E, F, G, H: E.C.2.4.2.17 - Atp phosphoribosyltransferase.

Pathway:

• Reaction: 1-(5-phospho-beta-D-ribosyl)-ATP + diphosphate = 5-phospho-alpha-D-ribose 1-diphosphate + ATP

1-(5-phospho-beta-D-ribosyl)-ATP + diphosphate (Bound ligand (Het Group name = PO4) matches with 55.56% similarity) = 5-phospho-alpha-D-ribose 1-diphosphate + ATP

Note, where more than one E.C. class is given (as above), each may correspond to a different protein domain or, in the case of polyprotein precursors, to a different mature protein.

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

reference

DOI no: 10.1074/jbc.M505041200

J Biol Chem 280:34096-34104 (2005)

PubMed id: 16051603

Activation of the hetero-octameric ATP phosphoribosyl transferase through subunit interface rearrangement by a tRNA synthetase paralog.

K.S.Champagne, M.Sissler, Y.Larrabee, S.Doublié, C.S.Francklyn.

ABSTRACT

ATP phosphoribosyl transferase (ATP-PRT) joins ATP and 5-phosphoribosyl-1-pyrophosphate (PRPP) in a highly regulated reaction that initiates histidine biosynthesis. The unusual hetero-octameric version of ATP-PRT includes four HisG(S) catalytic subunits based on the periplasmic binding protein fold and four HisZ regulatory subunits that resemble histidyl-tRNA synthetases. Here, we present the first structure of a PRPP-bound ATP-PRT at 2.9 A and provide a structural model for allosteric activation based on comparisons with other inhibited and activated ATP-PRTs from both the hetero-octameric and hexameric families. The activated state of the octameric enzyme is characterized by an interstitial phosphate ion in the HisZ-HisG interface and new contacts between the HisZ motif 2 loop and the HisG(S) dimer interface. These contacts restructure the interface to recruit conserved residues to the active site, where they activate pyrophosphate to promote catalysis. Additionally, mutational analysis identifies the histidine binding sites within a region highly conserved between HisZ and the functional HisRS. Through the oligomerization and functional re-assignment of protein domains associated with aminoacylation and phosphate binding, the HisZ-HisG octameric ATP-PRT acquired the ability to initiate the synthesis of a key metabolic intermediate in an allosterically regulated fashion.

Selected figure(s)

Figure 1.
The reaction catalyzed by ATP-phosphoribosyl transferase in L. lactis. The 5′-phosphoribosyl group of PRPP is transferred to ATP yielding PR-ATP and inorganic pyrophosphate (PPi). This reaction is dependant on magnesium and is inhibited by histidine, the end product of the pathway, and the cellular effectors AMP and ADP.

Figure 5.
Inter-subunit communications involved in activation/regulation of the HisZG ATP-PRTase. a, location of the interstitial phosphate ion in the interface between HisG (green) and HisZ (blue). The residues that coordinate the ion are close to a HisZ active site loop (magenta) that comprises part of the predicted histidine binding pocket. The interstitial phosphate is observed in only two of the four HisZ-HisG interfaces, namely those featuring an ordered motif 2 loop. b, interactions between the ordered HisZ motif 2 loop (blue) and the HisG dimer interface (green and gold). Motif 2 loop residues pack against strand β8 leading to the active site, whereas Arg-120 hydrogen bonds to Glu-59′ at the C-terminal end of helices α2 and α3.

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2005, 280, 34096-34104) copyright 2005.

Figures were selected by an automated process.