5TT5

Escherichia coli LigA (K115M) in complex with NAD+


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.55 Å
  • R-Value Free: 0.205 
  • R-Value Work: 0.176 
  • R-Value Observed: 0.178 

Starting Model: experimental
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Ligand Structure Quality Assessment 


This is version 1.4 of the entry. See complete history


Literature

Two-metal versus one-metal mechanisms of lysine adenylylation by ATP-dependent and NAD(+)-dependent polynucleotide ligases.

Unciuleac, M.C.Goldgur, Y.Shuman, S.

(2017) Proc Natl Acad Sci U S A 114: 2592-2597

  • DOI: https://doi.org/10.1073/pnas.1619220114
  • Primary Citation of Related Structures:  
    5TT5, 5TT6

  • PubMed Abstract: 

    Polynucleotide ligases comprise a ubiquitous superfamily of nucleic acid repair enzymes that join 3'-OH and 5'-PO 4 DNA or RNA ends. Ligases react with ATP or NAD + and a divalent cation cofactor to form a covalent enzyme-(lysine-Nζ)-adenylate intermediate. Here, we report crystal structures of the founding members of the ATP-dependent RNA ligase family (T4 RNA ligase 1; Rnl1) and the NAD + -dependent DNA ligase family ( Escherichia coli LigA), captured as their respective Michaelis complexes, which illuminate distinctive catalytic mechanisms of the lysine adenylylation reaction. The 2.2-Å Rnl1•ATP•(Mg 2+ ) 2 structure highlights a two-metal mechanism, whereby: a ligase-bound "catalytic" Mg 2+ (H 2 O) 5 coordination complex lowers the p K a of the lysine nucleophile and stabilizes the transition state of the ATP α phosphate; a second octahedral Mg 2+ coordination complex bridges the β and γ phosphates; and protein elements unique to Rnl1 engage the γ phosphate and associated metal complex and orient the pyrophosphate leaving group for in-line catalysis. By contrast, the 1.55-Å LigA•NAD + •Mg 2+ structure reveals a one-metal mechanism in which a ligase-bound Mg 2+ (H 2 O) 5 complex lowers the lysine p K a and engages the NAD + α phosphate, but the β phosphate and the nicotinamide nucleoside of the nicotinamide mononucleotide (NMN) leaving group are oriented solely via atomic interactions with protein elements that are unique to the LigA clade. The two-metal versus one-metal dichotomy demarcates a branchpoint in ligase evolution and favors LigA as an antibacterial drug target.


  • Organizational Affiliation

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


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
DNA ligase691Escherichia coli K-12Mutation(s): 1 
Gene Names: ligAdnaLligloppdeCb2411JW2403
EC: 6.5.1.2
UniProt
Find proteins for P15042 (Escherichia coli (strain K12))
Explore P15042 
Go to UniProtKB:  P15042
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP15042
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.55 Å
  • R-Value Free: 0.205 
  • R-Value Work: 0.176 
  • R-Value Observed: 0.178 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 40.907α = 90
b = 94.312β = 90
c = 150.927γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
HKL-2000data reduction
HKL-2000data scaling
MOLREPphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)United StatesGM63611-14
National Institutes of Health/National Cancer Institute (NIH/NCI)United StatesP30-CA008748

Revision History  (Full details and data files)

  • Version 1.0: 2017-03-08
    Type: Initial release
  • Version 1.1: 2017-03-22
    Changes: Database references
  • Version 1.2: 2017-09-20
    Changes: Author supporting evidence
  • Version 1.3: 2019-12-04
    Changes: Author supporting evidence
  • Version 1.4: 2023-10-04
    Changes: Data collection, Database references, Derived calculations, Refinement description