5SXT

Crystal structure of the S324T variant of Burkholderia pseudomallei KatG with isonicotinic acid hydrazide bound

Replaces:  3N3Q

Summary for 5SXT

• Entry DOI: 10.2210/pdb5sxt/pdb
• Related: 5L02 5L05 5SW4 5SW5 5SW6 5SX0 5SX1 5SX2 5SX3 5SX6 5SX7 5SXQ 5SXR 5SXS 5SXX 5SYH 5SYI 5SYJ 5SYK 5SYL 5SYU 5SYV 5SYW 5SYX 5SYY
• Descriptor: Catalase-peroxidase, PROTOPORPHYRIN IX CONTAINING FE, SODIUM ION, ... (9 entities in total)
• Functional Keywords: catalase-peroxidase, s324t variant, isoniazid, pro-drug activation, tuberculosis, oxidoreductase, katg
• Biological source: Burkholderia pseudomallei (strain 1710b)
• Total number of polymer chains: 2
• Total formula weight: 161248.44

Authors

Loewen, P.C. (deposition date: 2016-08-10, release date: 2016-09-07, Last modification date: 2024-10-23)

Primary citation

Wiseman, B.,Carpena, X.,Feliz, M.,Donald, L.J.,Pons, M.,Fita, I.,Loewen, P.C.
Isonicotinic acid hydrazide conversion to Isonicotinyl-NAD by catalase-peroxidases.
J. Biol. Chem., 285:26662-26673, 2010

PubMed Abstract: Activation of the pro-drug isoniazid (INH) as an anti-tubercular drug in Mycobacterium tuberculosis involves its conversion to isonicotinyl-NAD, a reaction that requires the catalase-peroxidase KatG. This report shows that the reaction proceeds in the absence of KatG at a slow rate in a mixture of INH, NAD(+), Mn(2+), and O(2), and that the inclusion of KatG increases the rate by >7 times. Superoxide, generated by either Mn(2+)- or KatG-catalyzed reduction of O(2), is an essential intermediate in the reaction. Elimination of the peroxidatic process by mutation slows the rate of reaction by 60% revealing that the peroxidatic process enhances, but is not essential for isonicotinyl-NAD formation. The isonicotinyl-NAD(*+) radical is identified as a reaction intermediate, and its reduction by superoxide is proposed. Binding sites for INH and its co-substrate, NAD(+), are identified for the first time in crystal complexes of Burkholderia pseudomallei catalase-peroxidase with INH and NAD(+) grown by co-crystallization. The best defined INH binding sites were identified, one in each subunit, on the opposite side of the protein from the entrance to the heme cavity in a funnel-shaped channel. The NAD(+) binding site is approximately 20 A from the entrance to the heme cavity and involves interactions primarily with the AMP portion of the molecule in agreement with the NMR saturation transfer difference results.

PubMed: 20554537
DOI: 10.1074/jbc.M110.139428

Experimental method

X-RAY DIFFRACTION (1.9 Å)