Lead identification for the K-Ras protein: virtual screening and combinatorial fragment-based approaches
Authors Pathan AAK, Panthi B, Khan Z, Koppula PR, Alanazi M, Sachchidanand S, Parine NR, Chourasia M
Received 2 November 2015
Accepted for publication 18 February 2016
Published 2 May 2016 Volume 2016:9 Pages 2575—2584
Checked for plagiarism Yes
Review by Single-blind
Peer reviewer comments 3
Editor who approved publication: Dr Faris Farassati
Akbar Ali Khan Pathan,1,2,* Bhavana Panthi,3,* Zahid Khan,1 Purushotham Reddy Koppula,4–6 Mohammed Saud Alanazi,1 Sachchidanand,3 Narasimha Reddy Parine,1 Mukesh Chourasia3,*
1Genome Research Chair (GRC), Department of Biochemistry, College of Science, King Saud University, 2Integrated Gulf Biosystems, Riyadh, Kingdom of Saudi Arabia; 3Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research, Hajipur, India; 4Department of Internal Medicine, School of Medicine, 5Harry S. Truman Memorial Veterans Affairs Hospital, 6Department of Radiology, School of Medicine, Columbia, MO, USA
*These authors contributed equally to this work
Objective: Kirsten rat sarcoma (K-Ras) protein is a member of Ras family belonging to the small guanosine triphosphatases superfamily. The members of this family share a conserved structure and biochemical properties, acting as binary molecular switches. The guanosine triphosphate-bound active K-Ras interacts with a range of effectors, resulting in the stimulation of downstream signaling pathways regulating cell proliferation, differentiation, and apoptosis. Efforts to target K-Ras have been unsuccessful until now, placing it among high-value molecules against which developing a therapy would have an enormous impact. K-Ras transduces signals when it binds to guanosine triphosphate by directly binding to downstream effector proteins, but in case of guanosine diphosphate-bound conformation, these interactions get disrupted.
Methods: In the present study, we targeted the nucleotide-binding site in the “on” and “off” state conformations of the K-Ras protein to find out suitable lead compounds. A structure-based virtual screening approach has been used to screen compounds from different databases, followed by a combinatorial fragment-based approach to design the apposite lead for the K-Ras protein.
Results: Interestingly, the designed compounds exhibit a binding preference for the “off” state over “on” state conformation of K-Ras protein. Moreover, the designed compounds’ interactions are similar to guanosine diphosphate and, thus, could presumably act as a potential lead for K-Ras. The predicted drug-likeness properties of these compounds suggest that these compounds follow the Lipinski’s rule of five and have tolerable absorption, distribution, metabolism, excretion and toxicity values.
Conclusion: Thus, through the current study, we propose targeting only “off” state conformations as a promising strategy for the design of reversible inhibitors to pharmacologically inhibit distinct conformations of K-Ras protein.
Keywords: antitumor agent, K-Ras, molecular docking, molecular modeling, virtual screening
Corrigendum for this paper has been published
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