Purkan Purkan1*, Sri Puji Astuti Wahyuningsih3, Wiwin Retnowati2, Diah Amelia1 and Alfain Noerdin Alimny1
1Biochemistry Research Division, Department of Chemistry, Faculty of Sciences and Technology, Airlangga University; Jl. Mulyorejo, Surabaya, 60115, Indonesia.
2Genetic Research Division, Department of Biology, Faculty of Sciences and Technology,
Airlangga University; Jl. Mulyorejo, Surabaya, 60115, Indonesia.
3Microbiology Laboratorium, Faculty of Medicine, Airlangga University;
Jl. Prof Moestopo, Surabaya, 60115, Indonesia.
Mutation in katG gene of Mycobacterium tuberculosis encoding catalase-peroxidase that damage its enzyme activities is wellassociated with isoniazid (INH) resistance. The katG gene from INH resistant strain of M. tuberculosis clinical isolate L19 has been observed in previous study, carrying mutations of G234A and C625T, andchanged the arginine residue at position 209 with cysteine in its KatG protein. However the activities of the mutant protein has been not known yet. Expression of the katG gene L19 that was done in Escherisicia coli BL21(DE3) using pCold II-DNA generated KatG protein with 80 kDa in SDS PAGE electroforegram. The mutant protein of KatG L19 decreased 43% of catalase activity and 11% of peroxidase activity against to KatG wild type (H37RV). The model structure of the mutantKatG protein had deviation structure toward KatG wtas 0,13 for number of Root Mean Square Deviations (RMSD). The mutant KatG (Arg209Cys) losedtwo hydrogen interactions and a van der Waals bond which present in KatG wild type. In the KatG wt protein, the both hydrogen bonds was formed between the Arg209 residu to Glu201, while the van der Waals bondoccured by lingking of Arg209residu to Glu217. Disruption in the some chemical interactionsmight trigger the decline in catalase-peroxidase activities of mutant KatG L19 and further it bring out the INH resistance in the clinical isolate L19.
Keywords: katG, catalase-peroxdase, isoniazid resistance, M. tuberculosis.