TY - JOUR

T1 - A HR-MS based method for the determination of chorismate synthase activity

AU - Khera, Harvinder K.

AU - Singh, Susheel K.

AU - Mir, Rafia

AU - Bharadwaj, Vikram

AU - Singh, Subhash

PY - 2017

Y1 - 2017

N2 - Chorismate synthase (Cs) catalyzes the last step of Shikimate pathway involving a unique biochemical reaction of anti-1,4 elimination of 3-phosphate group and the C-(6proR) hydrogen from 5-enolpyruvylshikimate-3-phosphate (EPSP) leading to the formation of chorismate, which is the common precursor for aromatic amino acid, ubiquinone, and folate biosynthesis in plants and several bacterial, fungal, and parasitic pathogens. Absence of Shikimate pathway in the vertebrate host, make Cs an appealing target for drug discovery against these pathogens. Here, we report a new method for detection of chorismate through a specific liquid chromatography, coupled with negative electrospray ionization high-resolution tandem mass spectrometry (ESI-HRMS) for determination of Cs enzyme activity. For this, we used a coupled enzyme reaction consisting of purified recombinant MtbEPSPs (EPSP synthase from Mycobacterium tuberculosis) for biosynthesis of EPSP, which is the substrate for Chorismate synthase along with MtbCs (Chorismate synthase both from Mycobacterium tuberculosis) for the formation of chorismate, followed by its detection through LC/HRMS. Since, the reaction components of Cs enzyme activity assay which otherwise may interfere with the other known spectrophotometric methods of checking Cs enzyme activity have no effect on this LC/HRMS based method, this method offer advantages over other existing methods for detection of Cs activity. Further, this LC/HRMS based method could be applicable for detection of enzyme activity of both monofunctional and bifunctional Cs from different species irrespective of their specific requirements of anaerobic or aerobic reaction conditions.

AB - Chorismate synthase (Cs) catalyzes the last step of Shikimate pathway involving a unique biochemical reaction of anti-1,4 elimination of 3-phosphate group and the C-(6proR) hydrogen from 5-enolpyruvylshikimate-3-phosphate (EPSP) leading to the formation of chorismate, which is the common precursor for aromatic amino acid, ubiquinone, and folate biosynthesis in plants and several bacterial, fungal, and parasitic pathogens. Absence of Shikimate pathway in the vertebrate host, make Cs an appealing target for drug discovery against these pathogens. Here, we report a new method for detection of chorismate through a specific liquid chromatography, coupled with negative electrospray ionization high-resolution tandem mass spectrometry (ESI-HRMS) for determination of Cs enzyme activity. For this, we used a coupled enzyme reaction consisting of purified recombinant MtbEPSPs (EPSP synthase from Mycobacterium tuberculosis) for biosynthesis of EPSP, which is the substrate for Chorismate synthase along with MtbCs (Chorismate synthase both from Mycobacterium tuberculosis) for the formation of chorismate, followed by its detection through LC/HRMS. Since, the reaction components of Cs enzyme activity assay which otherwise may interfere with the other known spectrophotometric methods of checking Cs enzyme activity have no effect on this LC/HRMS based method, this method offer advantages over other existing methods for detection of Cs activity. Further, this LC/HRMS based method could be applicable for detection of enzyme activity of both monofunctional and bifunctional Cs from different species irrespective of their specific requirements of anaerobic or aerobic reaction conditions.

KW - 5-enolpyruvylshikimate-3-phosphate

KW - Chorismate synthase

KW - Drug discovery

KW - Enzyme activity

KW - Mass spectrometry

KW - Mycobacterium tuberculosis

KW - Shikimate pathway

U2 - 10.2174/0929866523666161222153707

DO - 10.2174/0929866523666161222153707

M3 - Journal article

C2 - 28017143

AN - SCOPUS:85012005467

VL - 24

SP - 229

EP - 234

JO - Protein and Peptide Letters

JF - Protein and Peptide Letters

SN - 0929-8665

IS - 3

ER -