title: Comparative study of enzymatic activities of new KatG mutants from low- and high-level isoniazid-resistant clinical isolates of Mycobacterium tuberculosis.
abstract: Resistance to isoniazid (INH-R) in Mycobacterium tuberculosis is mainly due to mutations at position 315 (S315T) of the catalase-peroxidase KatG. We identified 16 mutations (including 13 biochemically uncharacterized mutations) in KatG from INH-R clinical isolates of M. tuberculosis showing mutations other than S315T. The KatG enzymatic activities (catalase, peroxidase, free radical production and isonicotinoyl-NAD formation) of wild-type KatG and the 16 mutants were determined and correlated to their spatial location in a KatG model structure. Of all mutations studied, H270R, which conferred a high level of INH-R and results in the disruption of a coordination bond with the heme, caused complete loss of all enzymatic KatG activities. The mutants generally associated with a very high level of INH-R were all characterized by a drastic reduction in catalase activity and a marked decrease in INH activation activities. One mutant, A162E, displayed a behavior similar to S315T, i.e. a moderate decrease in catalase activity and a drastic decrease in the formation of the radical form of INH. Finally, the mutants associated with a low level of INH-R showed a moderate reduction in the four catalytic activities, likely stemming from an overall alteration of the folding and/or stability of the KatG protein.
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CR7, INSERM, U1135, Centre d'Immunologie et des Maladies Infectieuses (CIMI), Team E13 (Bacteriology), Paris, France; AP-HP, Hôpital Pitié-Salpêtrière, Centre National de Référence des Mycobactéries et de la Résistance des Mycobactéries aux Antituberculeux (NRC MyrMA), Bactériologie-Hygiène, Paris, France. Electronic address: florence.brossier@psl.aphp.fr.
authors.forename: Florence
authors.initials: F
authors.lastname: Brossier
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CR7, INSERM, U1135, Centre d'Immunologie et des Maladies Infectieuses (CIMI), Team E13 (Bacteriology), Paris, France.
authors.forename: Marlène
authors.initials: M
authors.lastname: Boudinet
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CR7, INSERM, U1135, Centre d'Immunologie et des Maladies Infectieuses (CIMI), Team E13 (Bacteriology), Paris, France; AP-HP, Hôpital Pitié-Salpêtrière, Centre National de Référence des Mycobactéries et de la Résistance des Mycobactéries aux Antituberculeux (NRC MyrMA), Bactériologie-Hygiène, Paris, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Jarlier
authors.affiliation: Unité de Microbiologie Structurale, Institut Pasteur, CNRS URA 2185, 25 rue du Dr Roux, Paris, France; Université Paris Diderot, Sorbonne Paris Cité (Cellule Pasteur), 25 Rue du Dr Roux, 75015 Paris, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Petrella
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, CR7, INSERM, U1135, Centre d'Immunologie et des Maladies Infectieuses (CIMI), Team E13 (Bacteriology), Paris, France; AP-HP, Hôpital Pitié-Salpêtrière, Centre National de Référence des Mycobactéries et de la Résistance des Mycobactéries aux Antituberculeux (NRC MyrMA), Bactériologie-Hygiène, Paris, France.
authors.forename: Wladimir
authors.initials: W
authors.lastname: Sougakoff
mesh_terms: D000995:Antitubercular Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D002374:Catalase / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D024881:Drug Resistance, Bacterial / Q000235:genetics; D006801:Humans; D007538:Isoniazid / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests / Q000379:methods; D008958:Models, Molecular; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000187:drug effects / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification; D014376:Tuberculosis / Q000188:drug therapy / Q000382:microbiology*
chemical_list: D000995:Antitubercular Agents; D001426:Bacterial Proteins; D002374:Catalase; C480353:katG protein, Mycobacterium tuberculosis; D007538:Isoniazid
keywords: Catalase-peroxidase; Enzymatic activities; Isoniazid; KatG; Resistance; Tuberculosis