Structure of Lytic Transglycosylase MltE mutant Y192F from E.coli

Experimental Data Snapshot

  • Resolution: 2.33 Å
  • R-Value Free: 0.304 
  • R-Value Work: 0.234 
  • R-Value Observed: 0.237 

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A Structural Dissection of the Active Site of the Lytic Transglycosylase MltE from Escherichia coli.

Dik, D.A.Batuecas, M.T.Lee, M.Mahasenan, K.V.Marous, D.R.Lastochkin, E.Fisher, J.F.Hermoso, J.A.Mobashery, S.

(2018) Biochemistry 57: 6090-6098

  • DOI: https://doi.org/10.1021/acs.biochem.8b00800
  • Primary Citation of Related Structures:  
    6GHY, 6GHZ, 6GI3, 6GI4

  • PubMed Abstract: 

    Lytic transglycosylases (LTs) are bacterial enzymes that catalyze the cleavage of the glycan strands of the bacterial cell wall. The mechanism of this cleavage is a remarkable intramolecular transacetalization reaction, accomplished by an ensemble of active-site residues. Because the LT reaction occurs in parallel with the cell wall bond-forming reactions catalyzed by the penicillin-binding proteins, simultaneous inhibition of both enzymes can be particularly bactericidal to Gram-negative bacteria. The MltE lytic transglycosylase is the smallest of the eight LTs encoded by the Escherichia coli genome. Prior crystallographic and computational studies identified four active-site residues-E64, S73, S75, and Y192-as playing roles in catalysis. Each of these four residues was individually altered by mutation to give four variant enzymes (E64Q, S73A, S75A, and Y192F). All four variants showed reduced catalytic activity [soluble wild type (100%) > soluble Y192F and S75A (both 40%) > S73A (4%) > E64Q (≤1%)]. The crystal structure of each variant protein was determined at the resolution of 2.12 Å for E64Q, 2.33 Å for Y192F, 1.38 Å for S73A, and 1.35 Å for S75A. These variants show alteration of the hydrogen-bond interactions of the active site. Within the framework of a prior computational study of the LT mechanism, we suggest the mechanistic role of these four active-site residues in MltE catalysis.

  • Organizational Affiliation

    Department of Chemistry and Biochemistry , University of Notre Dame , 352 McCourtney Hall , Notre Dame , Indiana 46556 , United States.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Endo-type membrane-bound lytic murein transglycosylase AA [auth B],
B [auth A]
194Escherichia coli K-12Mutation(s): 1 
Gene Names: emtAmltEsltZycgPb1193JW5821
EC: 4.2.2
Find proteins for P0C960 (Escherichia coli (strain K12))
Explore P0C960 
Go to UniProtKB:  P0C960
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0C960
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.33 Å
  • R-Value Free: 0.304 
  • R-Value Work: 0.234 
  • R-Value Observed: 0.237 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 120.028α = 90
b = 181.339β = 90
c = 35.26γ = 90
Software Package:
Software NamePurpose
XDSdata reduction
Aimlessdata scaling

Structure Validation

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Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
Spanish Ministry of Economy and CompetitivenessSpainBFU2014-59389-P

Revision History  (Full details and data files)

  • Version 1.0: 2018-10-31
    Type: Initial release
  • Version 1.1: 2024-01-17
    Changes: Data collection, Database references, Refinement description