5AHE

Crystal structure of Salmonella enterica HisA


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Free: 0.206 
  • R-Value Work: 0.174 
  • R-Value Observed: 0.176 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

Two-Step Ligand Binding in a Beta/Alpha8 Barrel Enzyme -Substrate-Bound Structures Shed New Light on the Catalytic Cycle of Hisa

Soderholm, A.Guo, X.Newton, M.S.Evans, G.B.Nasvall, J.Patrick, W.M.Selmer, M.

(2015) J Biol Chem 290: 24657

  • DOI: 10.1074/jbc.M115.678086
  • Primary Citation of Related Structures:  
    5A5W, 5AHE, 5AHF

  • PubMed Abstract: 
  • HisA is a (βα)8 barrel enzyme that catalyzes the Amadori rearrangement of N'-[(5'-phosphoribosyl)formimino]-5-aminoimidazole-4-carboxamide ribonucleotide (ProFAR) to N'-((5'-phosphoribulosyl) formimino)-5-aminoimidazole-4-carboxamide-ribonucleotide ( ...

    HisA is a (βα)8 barrel enzyme that catalyzes the Amadori rearrangement of N'-[(5'-phosphoribosyl)formimino]-5-aminoimidazole-4-carboxamide ribonucleotide (ProFAR) to N'-((5'-phosphoribulosyl) formimino)-5-aminoimidazole-4-carboxamide-ribonucleotide (PRFAR) in the histidine biosynthesis pathway, and it is a paradigm for the study of enzyme evolution. Still, its exact catalytic mechanism has remained unclear. Here, we present crystal structures of wild type Salmonella enterica HisA (SeHisA) in its apo-state and of mutants D7N and D7N/D176A in complex with two different conformations of the labile substrate ProFAR, which was structurally visualized for the first time. Site-directed mutagenesis and kinetics demonstrated that Asp-7 acts as the catalytic base, and Asp-176 acts as the catalytic acid. The SeHisA structures with ProFAR display two different states of the long loops on the catalytic face of the structure and demonstrate that initial binding of ProFAR to the active site is independent of loop interactions. When the long loops enclose the substrate, ProFAR adopts an extended conformation where its non-reacting half is in a product-like conformation. This change is associated with shifts in a hydrogen bond network including His-47, Asp-129, Thr-171, and Ser-202, all shown to be functionally important. The closed conformation structure is highly similar to the bifunctional HisA homologue PriA in complex with PRFAR, thus proving that structure and mechanism are conserved between HisA and PriA. This study clarifies the mechanistic cycle of HisA and provides a striking example of how an enzyme and its substrate can undergo coordinated conformational changes before catalysis.


    Organizational Affiliation

    From the Department of Cell and Molecular Biology, Uppsala University, BMC, Box 596, 751 24 Uppsala, Sweden, maria.selmer@icm.uu.se.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
N/AA253Salmonella entericaMutation(s): 0 
EC: 5.3.1.16
Find proteins for P10372 (Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720))
Explore P10372 
Go to UniProtKB:  P10372
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 4 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
EPE
Query on EPE

Download Ideal Coordinates CCD File 
A
4-(2-HYDROXYETHYL)-1-PIPERAZINE ETHANESULFONIC ACID
C8 H18 N2 O4 S
JKMHFZQWWAIEOD-UHFFFAOYSA-N
 Ligand Interaction
PO4
Query on PO4

Download Ideal Coordinates CCD File 
A
PHOSPHATE ION
O4 P
NBIIXXVUZAFLBC-UHFFFAOYSA-K
 Ligand Interaction
GOL
Query on GOL

Download Ideal Coordinates CCD File 
A
GLYCEROL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
NA
Query on NA

Download Ideal Coordinates CCD File 
A
SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
CME
Query on CME
AL-PEPTIDE LINKINGC5 H11 N O3 S2CYS
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Free: 0.206 
  • R-Value Work: 0.174 
  • R-Value Observed: 0.176 
  • Space Group: P 61 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 86.769α = 90
b = 86.769β = 90
c = 121.53γ = 120
Software Package:
Software NamePurpose
PHENIXrefinement
XDSdata reduction
Aimlessdata scaling
PHASERphasing

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2015-09-02
    Type: Initial release
  • Version 1.1: 2015-10-21
    Changes: Database references