PyMOL, a cross‐platform molecular graphics tool, has been widely used for three‐dimensional (3D) visualization of proteins, nucleic acids, small molecules, electron densities, surfaces, and trajectories. It is also capable of editing molecules, ray tracing, and making movies. This Python‐based software, alongside many Python plugin tools, has been developed to enhance its utilities and facilitate the drug design in PyMOL. To gain an insightful view of useful drug design tools and their functions in PyMOL, we present an extensive discussion on various molecular modeling modules in PyMOL, covering those for visualization and analysis enhancement, protein–ligand modeling, molecular simulations, and drug screening. This review provides an excellent introduction to present 3D structures visualization and computational drug design in PyMOL. WIREs Comput Mol Sci 2017, 7:e1298. doi: 10.1002/wcms.1298 This article is categorized under: Structure and Mechanism > Molecular Structures Computer and Information Science > Visualization Molecular and Statistical Mechanics > Molecular Mechanics

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Towards ab initio screening of co-crystal formation through lattice energy calculations and crystal structure prediction of nicotinamide, isonicotinamide, picolinamide and paracetamol multi-component crystals3

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D-psicose 3-epimerase (DPEase) is demonstrated to be useful in the bioproduction of D-psicose, a rare hexose sugar, from D-fructose, found plenty in nature. Clostridium cellulolyticum H10 has recently been identified as a DPEase that can epimerize D-fructose to yield D-psicose with a much higher conversion rate when compared with the conventionally used DTEase. In this study, the crystal structure of the C. cellulolyticum DPEase was determined. The enzyme assembles into a tetramer and each subunit shows a (β/α)(8) TIM barrel fold with a Mn(2+) metal ion in the active site. Additional crystal structures of the enzyme in complex with substrates/products (D-psicose, D-fructose, D-tagatose and D-sorbose) were also determined. From the complex structures of C. cellulolyticum DPEase with D-psicose and D-fructose, the enzyme has much more interactions with D-psicose than D-fructose by forming more hydrogen bonds between the substrate and the active site residues. Accordingly, based on these ketohexose-bound complex structures, a C3-O3 proton-exchange mechanism for the conversion between D-psicose and D-fructose is proposed here. These results provide a clear idea for the deprotonation/protonation roles of E150 and E244 in catalysis.

Many central biological events rely on protein-ligand interactions. The identification and characterization of protein-binding sites for ligands are crucial for the understanding of functions of both endogenous ligands and synthetic drug molecules. G protein-coupled receptors (GPCRs) typically detect extracellular signal molecules on the cell surface and transfer these chemical signals across the membrane, inducing downstream cellular responses via G proteins or b-arrestin. GPCRs mediate many central physiological processes, making them important targets for modern drug discovery. Here, we focus on the most recent breakthroughs in finding new binding sites and binding modes of GPCRs and their potentials for the development of new medicines. The Classical Orthosteric Ligand-Binding Site G protein-coupled receptors (GPCRs; see Glossary) play an essential role in many physiological processes, including vision, olfaction and sense of smell, neuronal signal transmission, cell differentiation, pain, muscle contraction, and hormone secretion, to name a few [1-4]. Thus, GPCRs are among the most important targets for modern medicines (Box 1) [5]. Identifying the ligand-binding sites in target GPCRs is the first important step in a structure-based drug development process [6,7]. Recent progress in illuminating structures of GPCRs show that, besides binding to the traditional orthosteric site, ligands could also bind to remote allosteric sites (Table 1) which provide many new opportunities for drug discovery [7-12]. The traditional orthosteric site (Figure 1A) of GPCRs is close to the extracellular region of receptors, between a highly conserved W 6.48Â48 in transmembrane helix 6 (TM6) and extracellular loop 2 (ECL2). To define the relative position of each amino acid in a TM region, the generic residue numbering methods have been introduced for GPCRs (Box 2) [13]. Most residues (Figure 1B) frequently interacting with orthosteric ligands are in TM3 (positions 3.28

Human purinergic G protein-coupled receptor P2Y1 (P2Y1R) is activated by adenosine 5’-diphosphate (ADP) to induce platelet activation and thereby serves as an important antithrombotic drug target. Crystal structures of P2Y1R revealed that one ligand (MRS2500) binds to the extracellular vestibule of this GPCR, whereas another (BPTU) occupies the surface between transmembrane (TM) helices TM2 and TM3. We introduced a total of 20 µs all-atom long-timescale molecular dynamic (MD) simulations to inquire why two molecules in completely different locations both serve as antagonists while ADP activates the receptor. Our results indicate that BPTU acts as an antagonist by stabilizing extracellular helix bundles leading to an increase of the lipid order, whereas MRS2500 blocks signaling by occupying the ligand binding site. Both antagonists stabilize an ionic lock within the receptor. However, binding of ADP breaks this ionic lock, forming a continuous water channel that leads to P2Y1R activation.

We have obtained the structure of the bacterial diterpene synthase, tuberculosinol/iso-tuberculosinol synthase (Rv3378c) from Mycobacterium tuberculosis, a target for anti-infective therapies that block virulence factor formation. This phosphatase adopts the same fold as found in the Z- or cis-prenyltransferases. We also obtained structures containing the tuberculosinyl diphosphate substrate together with one bisphosphonate inhibitor-bound structure. These structures together with the results of site-directed mutagenesis suggest an unusual mechanism of action involving two Tyr residues. Given the similarity in local and global structure between Rv3378c and the M. tuberculosis cis-decaprenyl diphosphate synthase (DPPS; Rv2361c), the possibility exists for the development of inhibitors that target not only virulence but also cell wall biosynthesis, based in part on the structures reported here.