6Z22

Crystal structure of deacylation mutant KPC-4 (E166Q)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.40 Å
  • R-Value Free: 0.176 
  • R-Value Work: 0.140 
  • R-Value Observed: 0.142 

wwPDB Validation   3D Report Full Report


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Literature

Natural variants modify Klebsiella pneumoniae carbapenemase (KPC) acyl-enzyme conformational dynamics to extend antibiotic resistance.

Tooke, C.L.Hinchliffe, P.Bonomo, R.A.Schofield, C.J.Mulholland, A.J.Spencer, J.

(2020) J Biol Chem 296: 100126-100126

  • DOI: 10.1074/jbc.RA120.016461
  • Primary Citation of Related Structures:  
    6Z21, 6Z22, 6Z23, 6Z24, 6Z25

  • PubMed Abstract: 
  • Class A serine β-lactamases (SBLs) are key antibiotic resistance determinants in Gram-negative bacteria. SBLs neutralize β-lactams via a hydrolytically labile covalent acyl-enzyme intermediate. Klebsiella pneumoniae carbapenemase (KPC) is a widespread SBL that hydrolyzes carbapenems, the most potent β-lactams; known KPC variants differ in turnover of expanded-spectrum oxyimino-cephalosporins (ESOCs), for example, cefotaxime and ceftazidime ...

    Class A serine β-lactamases (SBLs) are key antibiotic resistance determinants in Gram-negative bacteria. SBLs neutralize β-lactams via a hydrolytically labile covalent acyl-enzyme intermediate. Klebsiella pneumoniae carbapenemase (KPC) is a widespread SBL that hydrolyzes carbapenems, the most potent β-lactams; known KPC variants differ in turnover of expanded-spectrum oxyimino-cephalosporins (ESOCs), for example, cefotaxime and ceftazidime. Here, we compare ESOC hydrolysis by the parent enzyme KPC-2 and its clinically observed double variant (P104R/V240G) KPC-4. Kinetic analyses show that KPC-2 hydrolyzes cefotaxime more efficiently than the bulkier ceftazidime, with improved ESOC turnover by KPC-4 resulting from enhanced turnover (k cat ), rather than altered K M values. High-resolution crystal structures of ESOC acyl-enzyme complexes with deacylation-deficient (E166Q) KPC-2 and KPC-4 mutants show that ceftazidime acylation causes rearrangement of three loops; the Ω, 240, and 270 loops, which border the active site. However, these rearrangements are less pronounced in the KPC-4 than the KPC-2 ceftazidime acyl-enzyme and are not observed in the KPC-2:cefotaxime acyl-enzyme. Molecular dynamics simulations of KPC:ceftazidime acyl-enyzmes reveal that the deacylation general base E166, located on the Ω loop, adopts two distinct conformations in KPC-2, either pointing "in" or "out" of the active site; with only the "in" form compatible with deacylation. The "out" conformation was not sampled in the KPC-4 acyl-enzyme, indicating that efficient ESOC breakdown is dependent upon the ordering and conformation of the KPC Ω loop. The results explain how point mutations expand the activity spectrum of the clinically important KPC SBLs to include ESOCs through their effects on the conformational dynamics of the acyl-enzyme intermediate.


    Organizational Affiliation

    School of Cellular and Molecular Medicine, Biomedical Sciences Building, University of Bristol, Bristol, United Kingdom. Electronic address: Jim.Spencer@bristol.ac.uk.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Beta-lactamaseA290Klebsiella pneumoniaeMutation(s): 1 
Gene Names: blaKPC-4blaKPC-2blakpckpc1
EC: 3.5.2.6
UniProt
Find proteins for Q9F663 (Klebsiella pneumoniae)
Explore Q9F663 
Go to UniProtKB:  Q9F663
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9F663
Protein Feature View
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  • Reference Sequence
Small Molecules
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.40 Å
  • R-Value Free: 0.176 
  • R-Value Work: 0.140 
  • R-Value Observed: 0.142 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 60.197α = 90
b = 78.941β = 90
c = 55.981γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
PDB_EXTRACTdata extraction
xia2data reduction
Aimlessdata scaling
PHASERphasing

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Medical Research Council (MRC, United Kingdom)United KingdomMR/T016035/1
Biotechnology and Biological Sciences Research Council (BBSRC)United KingdomBB/J014400/1

Revision History  (Full details and data files)

  • Version 1.0: 2020-12-23
    Type: Initial release
  • Version 1.1: 2021-07-21
    Changes: Database references