6C34

Mycobacterium smegmatis DNA flap endonuclease mutant D125N

  • Classification: DNA BINDING PROTEIN
  • Organism(s): Mycolicibacterium smegmatis MC2 155
  • Expression System: Escherichia coli
  • Mutation(s): Yes 

  • Deposited: 2018-01-09 Released: 2018-03-28 
  • Deposition Author(s): Shuman, S., Goldgur, Y., Carl, A., Uson, M.L.
  • Funding Organization(s): National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID), National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS), National Institutes of Health/National Center for Research Resources (NIH/NCRR), Department of Energy (DOE, United States)

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.226 
  • R-Value Work: 0.177 
  • R-Value Observed: 0.181 

wwPDB Validation   3D Report Full Report


This is version 1.4 of the entry. See complete history. 


Literature

Crystal structure and mutational analysis of Mycobacterium smegmatis FenA highlight active site amino acids and three metal ions essential for flap endonuclease and 5' exonuclease activities.

Uson, M.L., Carl, A., Goldgur, Y., Shuman, S.

(2018) Nucleic Acids Res 46: 4164-4175

  • DOI: 10.1093/nar/gky238
  • Primary Citation of Related Structures:  
    6C36, 6C33, 6C35, 6C34

  • PubMed Abstract: 

    • Mycobacterium smegmatis FenA is a nucleic acid phosphodiesterase with flap endonuclease and 5' exonuclease activities. The 1.8 Å crystal structure of FenA reported here highlights as its closest homologs bacterial FEN-family enzymes ExoIX, the Pol1 exonu ...

    Mycobacterium smegmatis FenA is a nucleic acid phosphodiesterase with flap endonuclease and 5' exonuclease activities. The 1.8 Å crystal structure of FenA reported here highlights as its closest homologs bacterial FEN-family enzymes ExoIX, the Pol1 exonuclease domain and phage T5 Fen. Mycobacterial FenA assimilates three active site manganese ions (M1, M2, M3) that are coordinated, directly and via waters, to a constellation of eight carboxylate side chains. We find via mutagenesis that the carboxylate contacts to all three manganese ions are essential for FenA's activities. Structures of nuclease-dead FenA mutants D125N, D148N and D208N reveal how they fail to bind one of the three active site Mn2+ ions, in a distinctive fashion for each Asn change. The structure of FenA D208N with a phosphate anion engaged by M1 and M2 in a state mimetic of a product complex suggests a mechanism for metal-catalyzed phosphodiester hydrolysis similar to that proposed for human Exo1. A distinctive feature of FenA is that it does not have the helical arch module found in many other FEN/FEN-like enzymes. Instead, this segment of FenA adopts a unique structure comprising a short 310 helix and surface β-loop that coordinates a fourth manganese ion (M4).

    Organizational Affiliation: 

    Molecular Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA.



Macromolecules
Find similar proteins by: 
(by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
5'-3' exonuclease A319Mycolicibacterium smegmatis MC2 155Mutation(s): 1 
Gene Names: MSMEI_3793
Find proteins for I7GAS0 (Mycolicibacterium smegmatis (strain ATCC 700084 / mc(2)155))
Explore I7GAS0 
Go to UniProtKB:  I7GAS0
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MN
Query on MN
Download Ideal Coordinates CCD File 
A
MANGANESE (II) ION
Mn
WAEMQWOKJMHJLA-UHFFFAOYSA-N		 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.226 
  • R-Value Work: 0.177 
  • R-Value Observed: 0.181 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 63.246α = 90
b = 39.878β = 108.8
c = 68.424γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
XDSdata reduction
XDSdata scaling
PHENIXphasing

Structure Validation

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View more in-depth experimental data

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)United StatesAI64693
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United StatesP41GM103403
National Institutes of Health/National Center for Research Resources (NIH/NCRR)United StatesHEI-S10RR029205
Department of Energy (DOE, United States)United StatesDE-AC02-06CH11357

Revision History 

  • Version 1.0: 2018-03-28
    Type: Initial release
  • Version 1.1: 2018-04-25
    Changes: Data collection, Database references
  • Version 1.2: 2018-05-16
    Changes: Data collection, Database references
  • Version 1.3: 2019-02-20
    Changes: Author supporting evidence, Data collection
  • Version 1.4: 2019-12-04
    Changes: Author supporting evidence