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Multi-oligomeric and catalytically compromised serine acetyltransferase and cysteine regulatory complex of Mycobacterium tuberculosis

DIR@IMTECH: CSIR-Institute of Microbial Technology

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Title Multi-oligomeric and catalytically compromised serine acetyltransferase and cysteine regulatory complex of Mycobacterium tuberculosis
 
Creator Rahisuddin, R.
Thakur, Payal
Kumar, Narender
Saini, Neha
Banerjee, Shrijta
Singh, Ravi Pratap
Patel, Madhuri
Kumaran, S.
 
Subject QR Microbiology
 
Description l-cysteine, a primary building block of mycothiol, plays an essential role in the defense mechanism of Mycobacterium tuberculosis (Mtb). However, it is unclear how Mtb regulates cysteine biosynthesis as no study has reported the cysteine regulatory complex (CRC) in Mtb. Serine acetyltransferase (SAT) and cysteine synthase (CS) interact to form CRC. Although MtCS has been characterized well, minimal information is available on MtSAT, which synthesizes, O-acetylserine (OAS), the precursor of cysteine. This study fills the gap and provides experimental evidence for the presence of MtCRC and a non-canonical multi-oligomeric MtSAT. We employed multiple analytical methods to characterize the oligomeric and kinetic properties of MtSAT and MtCRC. Results show that MtSAT, lacking >75 N-terminal amino acids exists in three different assembly states; trimer, hexamer, and dodecamer, compared to the single hexameric state of SAT of other bacteria. While hexamers display the highest catalytic turnover, the trimer is the least active. The predominance of trimers at low physiologically relevant concentrations suggests that MtSAT displays the lowest catalytic potential known. Further, the catalytic potential of MtSAT is also significantly reduced in CRC state, in contrast to enhanced activity of SAT in CRC of other organisms. Our study provides insights into multi-oligomeric MtSAT with reduced catalytic potential and demonstrates that both MtSAT and MtCS of Mycobacterium interact to form CRC, although with altered catalytic properties. We discuss our results in light of the altered biochemistry of the last step of canonical sulfate-dependent cysteine biosynthesis of Mycobacterium.
 
Publisher ELSEVIER
 
Date 2024-06
 
Type Article
PeerReviewed
 
Relation https://www.sciencedirect.com/science/article/pii/S0300908424000270#kwrds0010
http://crdd.osdd.net/open/3105/
 
Identifier Rahisuddin, R. and Thakur, Payal and Kumar, Narender and Saini, Neha and Banerjee, Shrijta and Singh, Ravi Pratap and Patel, Madhuri and Kumaran, S. (2024) Multi-oligomeric and catalytically compromised serine acetyltransferase and cysteine regulatory complex of Mycobacterium tuberculosis. BIOCHIMIE, 221. pp. 110-124.