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Structurally disordered C-terminal residues of GTP cyclohydrolase II are essential for its enzymatic activity

DIR@IMTECH: CSIR-Institute of Microbial Technology

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Title Structurally disordered C-terminal residues of GTP cyclohydrolase II are essential for its enzymatic activity
 
Creator Yadav, Savita
Shinde, Ranajit Nivrutti
Singh, Suruchi
Karthikeyan, Subramanian
Singh, Balvinder
 
Subject QR Microbiology
 
Description GTP cyclohydrolase II (GCHII) is one of the rate limiting enzymes in riboflavin biosynthesis pathway and is shown to be a potential drug target for most of the pathogens. Previous biochemical and structural studies have identified the active site residues and elucidated the steps involved in the catalytic mechanism of GCHII. However, the last ∼20–25 C-terminal residues of GCHII remains unstructured in all the crystal structures determined to date and their role in the catalytic activity, if any, remains elusive. Therefore, to understand the role of these unstructured C-terminal residues, a series of C-terminal deletion mutants of GCHII from Helicobacter pylori (hGCHII) were generated and their catalytic activity was compared with its wild-type. Surprisingly, none of the C-terminal deletion mutants shows any enzymatic activity indicating that these are essential for GCHII function. To get additional insights for such loss of activity, homology models of full-length and deletion mutants of hGCHII in complex with GTP, Mg2+, and Zn2+ were generated and subjected to molecular dynamics simulation studies. The simulation studies show that a conserved histidine at 190th position from the unstructured C-terminal region of hGCHII interacts with α-phosphate of GTP. We propose that His-190 may play a role in the hydrolysis of pyrophosphate from GTP and in releasing the product, DARP. In summary, we demonstrate that the unstructured C-terminal residues of GCHII are important for its enzymatic activity and must be considered during rational drug designing.
 
Publisher Taylor and Francis
 
Date 2021-05-25
 
Type Article
PeerReviewed
 
Relation https://www.tandfonline.com/doi/abs/10.1080/07391102.2021.1926326?journalCode=tbsd20
http://crdd.osdd.net/open/2768/
 
Identifier Yadav, Savita and Shinde, Ranajit Nivrutti and Singh, Suruchi and Karthikeyan, Subramanian and Singh, Balvinder (2021) Structurally disordered C-terminal residues of GTP cyclohydrolase II are essential for its enzymatic activity. JOURNAL OF BIOMOLECULAR STRUCTURE & DYNAMICS.