The lactose repressor protein may bind DNA in two possible configurations: a specific one, if the DNA sequence corresponds to a binding site, and a non-specific one otherwise. To find its target sequences, the lactose repressor first binds non-specifically to DNA, and subsequently, it rapidly searches for a binding site. Atomic structures of non-specific and specific complexes are available fro...

About 15 years ago, the steered molecular dynamics (SMD) was used to probe binding of ligand to biomolecule surfaces but in terms of drug design this approach has only recently attached attention of researchers. The main idea of using SMD to screen out leads is based on the hypothesis that the larger is the force needed to unbind a ligand from a receptor the higher its binding affinity. Thus, i...

Bruton's tyrosine kinase contains a pleckstrin homology domain, and it specifically binds inositol 1,3,4,5-tetrakisphosphate (Ins(1,3,4,5)P4), which is involved in the maturation of B cells. In this paper, we studied 12 systems including the wild type and 11 mutants, K12R, S14F, K19E, R28C/H, E41K, L11P, F25S, Y40N, and K12R-R28C/H, to investigate any change in the ligand binding site of each m...

Amyloid beta (Aβ) peptides are small cleavage products of the amyloid precursor protein. Aggregates of Aβ peptides are thought to be linked with Alzheimer's and other neurodegenerative diseases. Strategies aimed at inhibiting amyloid formation and promoting Aβ clearance have been proposed and investigated in in vitro experiments and in vivo therapies. A recent study indicated that a novel affib...

The correct representation of solute-water interactions is essential for the accurate simulation of most biological phenomena. Several highly accurate quantum methods are available to deal with solvation by using both implicit and explicit solvents. So far, however, most evaluations of those methods were based on a single conformation, which neglects solute entropy. Here, we present the first t...

Two neuraminidase inhibitors, oseltamivir and zanamivir, are important drug treatments for influenza. Oseltamivir-resistant mutants of the influenza virus A/H1N1 and A/H5N1 have emerged, necessitating the development of new long-acting antiviral agents. One such agent is a new neuraminidase inhibitor R-125489 and its prodrug CS-8958. An atomic level understanding of the nature of this antiviral...

The ectodomain of the human epidermal growth factor receptor (hEGFR) controls input to several cell signalling networks via binding with extracellular growth factors. To gain insight into the dynamics and ligand binding of the ectodomain, the hEGFR monomer was subjected to molecular dynamics simulation. The monomer was found to be substantially more flexible than the ectodomain dimer studied pr...

The oxy-myoglobin (Mb-O2) structure was probed by QM/MM (hybrid quantum mechanical/ molecular mechanical) calculations using DFT/MM to elucidate the effect of the heme propionates and the protein matrix on the chemistry of heme Fe-O2 moiety. On this line, we have probed the role of His97 in various protonation states of the heme propionate-6.

In order to compute polarization energy of biomolecules, we describe a boundary element approach to solving the linearized Poisson-Boltzmann equation. Our approach combines several important features including the derivative boundary formulation of the problem and a smooth approximation of the molecular surface based on the algebraic spline molecular surface. State of the art software for numer...

We have estimated affinities for the binding of 34 ligands to trypsin and nine guest molecules to three different hosts in the SAMPL3 blind challenge, using the MM/PBSA, MM/GBSA, LIE, continuum LIE, and Glide score methods. For the trypsin challenge, none of the methods were able to accurately predict the experimental results. For the MM/GB(PB)SA and LIE methods, the rankings were essentially r...