5IQW

1.95A resolution structure of Apo HasAp (R33A) from Pseudomonas aeruginosa


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.95 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.185 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Replacing Arginine 33 for Alanine in the Hemophore HasA from Pseudomonas aeruginosa Causes Closure of the H32 Loop in the Apo-Protein.

Kumar, R.Qi, Y.Matsumura, H.Lovell, S.Yao, H.Battaile, K.P.Im, W.Moenne-Loccoz, P.Rivera, M.

(2016) Biochemistry 55: 2622-2631

  • DOI: 10.1021/acs.biochem.6b00239
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Previous characterization of hemophores from Serratia marcescens (HasAs), Pseudomonas aeruginosa (HasAp), and Yersinia pestis (HasAyp) showed that hemin binds between two loops, where it is axially coordinated by H32 and Y75. The Y75 loop is structur ...

    Previous characterization of hemophores from Serratia marcescens (HasAs), Pseudomonas aeruginosa (HasAp), and Yersinia pestis (HasAyp) showed that hemin binds between two loops, where it is axially coordinated by H32 and Y75. The Y75 loop is structurally conserved in all three hemophores and harbors conserved ligand Y75. The other loop contains H32 in HasAs and HasAp, but a noncoordinating Q32 in HasAyp. The H32 loop in apo-HasAs and apo-HasAp is in an open conformation, which places H32 about 30 Å from the hemin-binding site. Hence, hemin binding onto the Y75 loop of HasAs or HasAp triggers a large relocation of the H32 loop from an open- to a closed-loop conformation and enables coordination of the hemin-iron by H32. In comparison, the Q32 loop in apo-HasAyp is in the closed conformation, and hemin binding occurs with minimal reorganization and without coordinative interactions with the Q32 loop. Studies in crystallo and in solution have established that the open H32 loop in apo-HasAp and apo-HasAs is well structured and minimally affected by conformational dynamics. In this study we address the intriguing issue of the stability of the H32 loop in apo-HasAp and how hemin binding triggers its relocation. We address this question with a combination of NMR spectroscopy, X-ray crystallography, and molecular dynamics simulations and find that R33 is critical to the stability of the open H32 loop. Replacing R33 with A causes the H32 loop in R33A apo-HasAp to adopt a conformation similar to that of holo-HasAp. Finally, stopped-flow absorption and resonance Raman analyses of hemin binding to apo-R33A HasAp indicate that the closed H32 loop slows down the insertion of the heme inside the binding pocket, presumably as it obstructs access to the hydrophobic platform on the Y75 loop, but accelerates the completion of the heme iron coordination.


    Organizational Affiliation

    Division of Environmental & Biomolecular Systems, Institute of Environmental Health, Oregon Health and Science University , 3181 SW Sam Jackson Park Road, Oregon 97239, United States.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Heme acquisition protein HasAp
A
184Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 / JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1)Mutation(s): 1 
Gene Names: hasAp
Find proteins for G3XD33 (Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 / JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1))
Go to UniProtKB:  G3XD33
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ACT
Query on ACT

Download SDF File 
Download CCD File 
A
ACETATE ION
C2 H3 O2
QTBSBXVTEAMEQO-UHFFFAOYSA-M
 Ligand Interaction
CD
Query on CD

Download SDF File 
Download CCD File 
A
CADMIUM ION
Cd
WLZRMCYVCSSEQC-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.95 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.185 
  • Space Group: P 41 21 2
Unit Cell:
Length (Å)Angle (°)
a = 92.781α = 90.00
b = 92.781β = 90.00
c = 95.714γ = 90.00
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
Aimlessdata scaling
XDSdata reduction
PHENIXrefinement
PHASERphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Science Foundation (United States)United StatesMCB0818488, MCB1158469

Revision History 

  • Version 1.0: 2016-04-20
    Type: Initial release
  • Version 1.1: 2016-05-18
    Type: Database references
  • Version 1.2: 2017-09-20
    Type: Author supporting evidence, Database references, Derived calculations
  • Version 1.3: 2017-11-01
    Type: Author supporting evidence