5JSR

New Mechanistic Insight from Substrate and Product Bound Structures of the Metal-dependent Dimethylsulfoniopropionate Lyase DddQ


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.247 
  • R-Value Work: 0.211 
  • R-Value Observed: 0.213 

Starting Model: experimental
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This is version 1.2 of the entry. See complete history


Literature

New Mechanistic Insight from Substrate- and Product-Bound Structures of the Metal-Dependent Dimethylsulfoniopropionate Lyase DddQ.

Brummett, A.E.Dey, M.

(2016) Biochemistry 55: 6162-6174

  • DOI: https://doi.org/10.1021/acs.biochem.6b00585
  • Primary Citation of Related Structures:  
    5JSO, 5JSP, 5JSR

  • PubMed Abstract: 

    The marine microbial catabolism of dimethylsulfoniopropionate (DMSP) by the lyase pathway liberates ∼300 million tons of dimethyl sulfide (DMS) per year, which plays a major role in the biogeochemical cycling of sulfur. Recent biochemical and structural studies of some DMSP lyases, including DddQ, reveal the importance of divalent transition metal ions in assisting DMSP cleavage. While DddQ is believed to be zinc-dependent primarily on the basis of structural studies, excess zinc inhibits the enzyme. We examine the importance of iron in regulating the DMSP β-elimination reaction catalyzed by DddQ as our as-isolated purple-colored enzyme possesses ∼0.5 Fe/subunit. The UV-visible spectrum exhibited a feature at 550 nm, consistent with a tyrosinate-Fe(III) ligand-to-metal charge transfer transition. Incubation of as-isolated DddQ with added iron increases the intensity of the 550 nm peak, whereas addition of dithionite causes a bleaching as Fe(III) is reduced. Both the Fe(III) oxidized and Fe(II) reduced species are active, with similar k cat values and 2-fold differences in their K m values for DMSP. The slow turnover of Fe(III)-bound DddQ allowed us to capture a substrate-bound form of the enzyme. Our DMSP-Fe(III)-DddQ structure reveals conformational changes associated with substrate binding and shows that DMSP is positioned optimally to bind iron and is in the proximity of Tyr 120 that acts as a Lewis base to initiate catalysis. The structures of Tris-, DMSP-, and acrylate-bound forms of Fe(III)-DddQ reported here illustrate various states of the enzyme along the reaction pathway. These results provide new insights into DMSP lyase catalysis and have broader significance for understanding the mechanism of oceanic DMS production.


  • Organizational Affiliation

    Department of Chemistry, The University of Iowa , Iowa City, Iowa 52242, United States.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Dimethlysulfonioproprionate lyase DddQ
A, B
201Ruegeria lacuscaerulensis ITI-1157Mutation(s): 0 
Gene Names: dddQSL1157_0332
EC: 4.4.1.3
UniProt
Find proteins for D0CY60 (Ruegeria lacuscaerulensis (strain DSM 11314 / KCTC 2953 / ITI-1157))
Explore D0CY60 
Go to UniProtKB:  D0CY60
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupD0CY60
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 4 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
BR
Query on BR

Download Ideal Coordinates CCD File 
E [auth A],
K [auth B]
BROMIDE ION
Br
CPELXLSAUQHCOX-UHFFFAOYSA-M
AKR
Query on AKR

Download Ideal Coordinates CCD File 
D [auth A],
J [auth B]
ACRYLIC ACID
C3 H4 O2
NIXOWILDQLNWCW-UHFFFAOYSA-N
FE
Query on FE

Download Ideal Coordinates CCD File 
C [auth A],
I [auth B]
FE (III) ION
Fe
VTLYFUHAOXGGBS-UHFFFAOYSA-N
CL
Query on CL

Download Ideal Coordinates CCD File 
F [auth A],
G [auth A],
H [auth A],
L [auth B],
M [auth B]
CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.247 
  • R-Value Work: 0.211 
  • R-Value Observed: 0.213 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 48.724α = 90
b = 88.17β = 90
c = 93.082γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
SCALAdata scaling
PDB_EXTRACTdata extraction
PHASERphasing
XDSdata reduction

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
University of Iowa, College of Liberal Arts and SciencesUnited States--

Revision History  (Full details and data files)

  • Version 1.0: 2017-02-22
    Type: Initial release
  • Version 1.1: 2017-03-01
    Changes: Derived calculations
  • Version 1.2: 2023-09-27
    Changes: Data collection, Database references, Derived calculations, Refinement description