Conserved water mediated recognition and the dynamics of active site Cys 331 and Tyr 411 in hydrated structure of human IMPDH-II

✍ Scribed by Hridoy R. Bairagya; Bishnu P. Mukhopadhyay; Asim K. Bera

• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 410 KB
• Volume: 24
• Category: Article
• ISSN: 0952-3499
• DOI: 10.1002/jmr.1021

✦ Synopsis

Inosine monophosphate dehydrogenase (IMPDH) of human is involved in GMP biosynthesis pathway, increased level of IMPDH-II (an isoform of enzyme) activity have found in leukemic and sarcoma cells. Modeling and extensive molecular dynamics simulation (15 ns) studies of IMPDH-II (1B3O PDB structure) have indicated the intricate involvement of four conserved water molecules (W 1, W 2, W 3, and W 4) in the conformational transition or the mobilities of "flap" (residues 400-450) and "loop" (residues 325-342) regions in enzyme. The stabilization of active site residues Asn 303, Gly 324, Ser 329, Cys 331, Asp 364, and Tyr 411 through variable H-bonding coordination from the conserved water molecular center seems interesting in the uninhibited hydrated form of human IMPDH-II structures. This conformational transition or the flexibility of mobile regions, water molecular recognition to active site residues Cys 331 and Tyr 411, and the presence of a hydrophilic cavity approximately 540 Å(3) (enclaved by the loop and flap region) near the C-terminal surface of this enzyme may explore a rational hope toward the water mimic inhibitor or anticancer agent design for human.