2J7V

Structure of PBP-A


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.213 
  • R-Value Work: 0.172 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structure of Pbp-A from Thermosynechococcus Elongatus, a Penicillin-Binding Protein Closely Related to Class a Beta-Lactamases.

Urbach, C.Evrard, C.Pudzaitis, V.Fastrez, J.Soumillion, P.Declercq, J.P.

(2009) J.Mol.Biol. 386: 109

  • DOI: 10.1016/j.jmb.2008.12.001
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Molecular evolution has always been a subject of discussions, and researchers are interested in understanding how proteins with similar scaffolds can catalyze different reactions. In the superfamily of serine penicillin-recognizing enzymes, D-alanyl- ...

    Molecular evolution has always been a subject of discussions, and researchers are interested in understanding how proteins with similar scaffolds can catalyze different reactions. In the superfamily of serine penicillin-recognizing enzymes, D-alanyl-D-alanine peptidases and beta-lactamases are phylogenetically linked but feature large differences of reactivity towards their respective substrates. In particular, while beta-lactamases hydrolyze penicillins very fast, leading to their inactivation, these molecules inhibit d-alanyl-d-alanine peptidases by forming stable covalent penicilloyl enzymes. In cyanobacteria, we have discovered a new family of penicillin-binding proteins (PBPs) presenting all the sequence features of class A beta-lactamases but having a six-amino-acid deletion in the conserved Omega-loop and lacking the essential Glu166 known to be involved in the penicillin hydrolysis mechanism. With the aim of evolving a member of this family into a beta-lactamase, PBP-A from Thermosynechococcus elongatus has been chosen because of its thermostability. Based on sequence alignments, introduction of a glutamate in position 158 of the shorter Omega-loop afforded an enzyme with a 50-fold increase in the rate of penicillin hydrolysis. The crystal structures of PBP-A in the free and penicilloylated forms at 1.9 A resolution and of L158E mutant at 1.5 A resolution were also solved, giving insights in the catalytic mechanism of the proteins. Since all the active-site elements of PBP-A-L158E, including an essential water molecule, are almost perfectly superimposed with those of a class A beta-lactamase such as TEM-1, the question why our mutant is still 5 orders of magnitude less active as a penicillinase remains and our results emphasize how far we are from understanding the secrets of enzymes. Based on the few minor differences between the active sites of PBP-A and TEM-1, mutations were introduced in the L158E enzyme, but while activities on D-Ala-D-Ala mimicking substrates were severely impaired, further improvement in penicillinase activity was unsuccessful.


    Organizational Affiliation

    Laboratoire d'Ingénierie des Protéines et des Peptides, Institut des Sciences de la Vie, Université catholique de Louvain, Place Croix du Sud 4-5, bte3, 1348 Louvain la-Neuve, Belgium.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
TLL2115 PROTEIN
A, B, C, D
298Thermosynechococcus elongatus (strain BP-1)Mutation(s): 0 
Find proteins for Q8DH45 (Thermosynechococcus elongatus (strain BP-1))
Go to UniProtKB:  Q8DH45
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.213 
  • R-Value Work: 0.172 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 87.790α = 90.00
b = 91.900β = 90.00
c = 147.270γ = 90.00
Software Package:
Software NamePurpose
PHASERphasing
REFMACrefinement
XSCALEdata scaling
XDSdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2007-11-06
    Type: Initial release
  • Version 1.1: 2011-06-09
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance