Document Detail

Allosteric inhibition of VIM metallo-β-lactamases by a camelid nanobody.
MedLine Citation:
PMID:  23289540     Owner:  NLM     Status:  Publisher    
Metallo-β-lactamase (MβL) enzymes are usually produced by multiresistant Gram-negative bacterial strains and have spread worldwide. An approach based on phage display was employed to select single-domain antibody fragments (VHHs also called Nanobodies) that would inhibit the clinically relevant VIM-4 MβL. Out of more than 50 selected nanobodies, only the NbVIM_38 nanobody inhibited VIM-4. The paratope, inhibition mechanism and epitope of NbVIM_38 nanobody were then characterised. An alanine scan of the NbVIM_38 paratope showed that its binding was driven by hydrophobic amino acids. The inhibitory concentration was in the µM range for all tested β-lactams. In addition, the inhibition was found to follow a mixed hyperbolic profile with a predominantly uncompetitive component. Moreover, substrate inhibition was recorded only after nanobody binding. These kinetic data are indicative of a binding site that is distant from the active site. This finding was confirmed by epitope mapping analysis that was performed using peptides, and which identified two stretches of amino acids in the L6 loop and the end of the α2 helix. Because this binding site is distant from the active site and alters both the substrate binding and catalytic properties of VIM-4, this nanobody can be considered as an allosteric inhibitor.
Jean Sebastien Sohier; Clémentine Laurent; Andy Chevigné; Els Pardon; Vasundara Srinivasan; Ulrich Wernery; Jan Steyaert; Moreno Galleni
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2013-1-7
Journal Detail:
Title:  The Biochemical journal     Volume:  -     ISSN:  1470-8728     ISO Abbreviation:  Biochem. J.     Publication Date:  2013 Jan 
Date Detail:
Created Date:  2013-1-7     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  2984726R     Medline TA:  Biochem J     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
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