Elucidating the function of hypothetical PE_PGRS45 protein of <i>Mycobacterium tuberculosis</i> as an oxido-reductase: a potential target for drug repurposing for the treatment of tuberculosis
Creators: name: Medha
name: Joshi, Hemant
name: Sharma, Sadhna
name: Sharma, Monika
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Biochemistry
subject: Microbiology
subject: FOS: Biological sciences
subject: Cell Biology
subject: Genetics
subject: Molecular Biology
subject: Pharmacology
subject: Biotechnology
subject: Chemical Sciences not elsewhere classified
subject: Immunology
subject: FOS: Clinical medicine
subject: Biological Sciences not elsewhere classified
subject: Information Systems not elsewhere classified
subject: Cancer
subject: Hematology
subject: Infectious Diseases
subject: FOS: Health sciences

description: <i>Mycobacterium tuberculosis</i> (Mtb) encodes a total of 67 PE_PGRS proteins and definite functions of many of them are still unknown. This study reports PE_PGRS45 (Rv2615c) protein from Mtb as NADPH dependent oxido-reductase having substrate specificity for fatty acyl Coenzyme A. Computational studies predicted PE_PGRS45 to be an integral membrane protein of Mtb. Expression of PE_PGRS45 in non-pathogenic <i>Mycobacterium smegmatis</i>, which does not possess PE_PGRS genes, confirmed its membrane localization. This protein was observed to have NADPH binding motif. Experimental validation confirmed its NADPH dependent oxido-reductase activity (Km value = 34.85 ± 9.478 μM, Vmax = 96.77 ± 7.184 nmol/min/mg of protein). Therefore, its potential to be targeted by first line anti-tubercular drug Isoniazid (INH) was investigated. INH was predicted to bind within the active site of PE_PGRS45 protein and experiments validated its inhibitory effect on the oxido-reductase activity of PE_PGRS45 with IC<sub>50</sub>/Ki values of 5.66 μM. Mtb is resistant to first line drugs including INH. Therefore, to address the problem of drug resistant TB, docking and Molecular Dynamics (MD) simulation studies between PE_PGRS45 and three drugs (Entacapone, Tolcapone and Verapamil) which are being used in Parkinson’s and hypertension treatment were performed. PE_PGRS45 bound the three drugs with similar or better affinity in comparison to INH. Additionally, INH and these drugs bound within the same active site of PE_PGRS45. This study discovered Mtb’s PE_PGRS45 protein to have an oxido-reductase activity and could be targeted by drugs that can be repurposed for TB treatment. Furthermore, <i>in-vitro</i> and <i>in-vivo</i> validation will aid in drug-resistant TB treatment.
HIGHLIGHTS<i>In-silico</i> and <i>in-vitro</i> studies of hypothetical protein PE_PGRS45 (Rv2615c) of <i>Mycobacterium tuberculosis</i> (Mtb) reveals it to be an integral membrane proteinPE_PGRS45 protein has substrate specificity for fatty acyl Coenzyme A (fatty acyl CoA) and possess NADPH dependent oxido-reductase activityDocking and simulation studies revealed that first line anti-tubercular drug Isoniazid (INH) and other drugs with anti-TB property have strong affinity for PE_PGRS45 proteinOxido-reductase activity of PE_PGRS45 protein is inhibited by INHPE_PGRS45 protein could be targeted by drugs that can be repurposed for TB treatment <i>In-silico</i> and <i>in-vitro</i> studies of hypothetical protein PE_PGRS45 (Rv2615c) of <i>Mycobacterium tuberculosis</i> (Mtb) reveals it to be an integral membrane protein PE_PGRS45 protein has substrate specificity for fatty acyl Coenzyme A (fatty acyl CoA) and possess NADPH dependent oxido-reductase activity Docking and simulation studies revealed that first line anti-tubercular drug Isoniazid (INH) and other drugs with anti-TB property have strong affinity for PE_PGRS45 protein Oxido-reductase activity of PE_PGRS45 protein is inhibited by INH PE_PGRS45 protein could be targeted by drugs that can be repurposed for TB treatment Communicated by Ramaswamy H. Sarma