4Z06

C. bescii Family 3 pectate lyase double mutant K108A/R133A in complex with ALPHA-D-GALACTOPYRANURONIC ACID


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.55 Å
  • R-Value Free: 0.200 
  • R-Value Work: 0.160 
  • R-Value Observed: 0.162 

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Ligand Structure Quality Assessment 


This is version 1.4 of the entry. See complete history


Literature

The catalytic mechanism and unique low pH optimum of Caldicellulosiruptor bescii family 3 pectate lyase.

Alahuhta, M.Taylor, L.E.Brunecky, R.Sammond, D.W.Michener, W.Adams, M.W.Himmel, M.E.Bomble, Y.J.Lunin, V.

(2015) Acta Crystallogr D Biol Crystallogr 71: 1946-1954

  • DOI: https://doi.org/10.1107/S1399004715013760
  • Primary Citation of Related Structures:  
    4YZ0, 4YZA, 4YZQ, 4YZX, 4Z03, 4Z05, 4Z06

  • PubMed Abstract: 

    The unique active site of the Caldicellulosiruptor bescii family 3 pectate lyase (PL3) enzyme has been thoroughly characterized using a series of point mutations, X-ray crystallography, pK(a) calculations and biochemical assays. The X-ray structures of seven PL3 active-site mutants, five of them in complex with intact trigalacturonic acid, were solved and characterized structurally, biochemically and computationally. The results confirmed that Lys108 is the catalytic base, but there is no clear candidate for the catalytic acid. However, the reaction mechanism can also be explained by an antiperiplanar trans-elimination reaction, in which Lys108 abstracts a proton from the C5 atom without the help of simultaneous proton donation by an acidic residue. An acidified water molecule completes the anti β-elimination reaction by protonating the O4 atom of the substrate. Both the C5 hydrogen and C4 hydroxyl groups of the substrate must be orientated in axial configurations, as for galacturonic acid, for this to be possible. The wild-type C. bescii PL3 displays a pH optimum that is lower than that of Bacillus subtilis PL1 according to activity measurements, indicating that C. bescii PL3 has acquired a lower pH optimum by utilizing lysine instead of arginine as the catalytic base, as well as by lowering the pK(a) of the catalytic base in a unique active-site environment.


  • Organizational Affiliation

    BioSciences Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Pectate lyase
A, B
204Caldicellulosiruptor bescii DSM 6725Mutation(s): 2 
Gene Names: Athe_1854
EC: 4.2.2.2
UniProt
Find proteins for B9MKT4 (Caldicellulosiruptor bescii (strain ATCC BAA-1888 / DSM 6725 / KCTC 15123 / Z-1320))
Explore B9MKT4 
Go to UniProtKB:  B9MKT4
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupB9MKT4
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 4 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
ADA
Query on ADA

Download Ideal Coordinates CCD File 
G [auth A],
P [auth B]
alpha-D-galactopyranuronic acid
C6 H10 O7
AEMOLEFTQBMNLQ-BKBMJHBISA-N
MPD
Query on MPD

Download Ideal Coordinates CCD File 
I [auth A],
J [auth A],
K [auth A],
Q [auth B]
(4S)-2-METHYL-2,4-PENTANEDIOL
C6 H14 O2
SVTBMSDMJJWYQN-YFKPBYRVSA-N
MRD
Query on MRD

Download Ideal Coordinates CCD File 
H [auth A](4R)-2-METHYLPENTANE-2,4-DIOL
C6 H14 O2
SVTBMSDMJJWYQN-RXMQYKEDSA-N
CA
Query on CA

Download Ideal Coordinates CCD File 
C [auth A]
D [auth A]
E [auth A]
F [auth A]
L [auth B]
C [auth A],
D [auth A],
E [auth A],
F [auth A],
L [auth B],
M [auth B],
N [auth B],
O [auth B]
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.55 Å
  • R-Value Free: 0.200 
  • R-Value Work: 0.160 
  • R-Value Observed: 0.162 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 137.68α = 90
b = 36.24β = 132.53
c = 99.82γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
XDSdata reduction
XSCALEdata scaling
MOLREPphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Department of Energy (DOE, United States)United States--

Revision History  (Full details and data files)

  • Version 1.0: 2015-12-23
    Type: Initial release
  • Version 1.1: 2017-09-20
    Changes: Author supporting evidence, Derived calculations
  • Version 1.2: 2019-12-04
    Changes: Author supporting evidence
  • Version 1.3: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Data collection, Derived calculations, Structure summary
  • Version 1.4: 2024-03-06
    Changes: Data collection, Database references, Structure summary