Multi-level meta-workflows: new concept for regularly occurring tasks in quantum chemistry.

BACKGROUND: In Quantum Chemistry, many tasks are reoccurring frequently, e.g. geometry optimizations, benchmarking series etc. Here, workflows can help to reduce the time of manual job definition and output extraction. These workflows are executed on computing infrastructures and may require large computing and data resources. Scientific workflows hide these infrastructures and the resources needed to run them. It requires significant efforts and specific expertise to design, implement and test these workflows. SIGNIFICANCE: Many of these workflows are complex and monolithic entities that can be used for particular scientific experiments. Hence, their modification is not straightforward and it makes almost impossible to share them. To address these issues we propose developing atomic workflows and embedding them in meta-workflows. Atomic workflows deliver a well-defined research domain specific function. Publishing workflows in repositories enables workflow sharing inside and/or among scientific communities. We formally specify atomic and meta-workflows in order to define data structures to be used in repositories for uploading and sharing them. Additionally, we present a formal description focused at orchestration of atomic workflows into meta-workflows. CONCLUSIONS: We investigated the operations that represent basic functionalities in Quantum Chemistry, developed the relevant atomic workflows and combined them into meta-workflows. Having these workflows we defined the structure of the Quantum Chemistry workflow library and uploaded these workflows in the SHIWA Workflow Repository.Graphical AbstractMeta-workflows and embedded workflows in the template representation.

Application repository and science gateway for running molecular docking and dynamics simulations.

Molecular docking and dynamics studies are of considerable importance in a range of disciplines including molecular biology, drug design, environmental studies, psychology, etc. Using in silico tools to support or even to substitute wet laboratory work could help better focusing the laboratory experiments resulting not only in considerable saving of resources but also increasing the number of molecules and scenarios investigated. There are several software packages that support in silico modeling. However, these tools require lot of compute resources and special technical knowledge. As a result, many bio-scientists cannot use them. The paper describes a science gateway based solution which provides access to Distributed Computing Infrastructures such as clouds, desktop and service grids. This environment enables bio-scientists to execute simple molecular modeling scenarios or build more complex use-cases from existing building blocks while hiding the technical details of the infrastructure. Four scenarios have been defined and deconstructed in order to identify common building blocks supporting a large number of complex use-cases. A reference implementation for the first scenario regarding the impact on indicator species of pharmaceuticals released into water courses has been implemented on the EDGI infrastructure, demonstrating the feasibility of the approach.

Cation-π interactions induce kinking of a molecular hinge in the RNA polymerase bridge-helix domain.

RNAPs (RNA polymerases) are complex molecular machines that contain a highly conserved catalytic site surrounded by conformationally flexible domains. High-throughput mutagenesis in the archaeal model system Methanocaldococcus jannaschii has demonstrated that the nanomechanical properties of one of these domains, the bridge-helix, exert a key regulatory role on the rate of the NAC (nucleotide-addition cycle). Mutations that increase the probability and/or half-life of kink formation in the BH-HC (bridge-helix C-terminal hinge) cause a substantial increase in specific activity ('superactivity'). Fully atomistic molecular dynamics simulations show that kinking of the BH-HC appears to be driven by cation-π interactions and involve amino acid side chains that are exceptionally highly conserved in all prokaryotic and eukaryotic species.

Integrating Open Grid Services Architecture Data Access and Integration with computational Grid workflows.

Although many scientific applications rely on data stored in databases, most workflow management systems are not capable of establishing database connections during workflow execution. For this reason, e-Scientists have to use different tools before workflow submission to access their datasets and gather the required data on which they want to carry out computational experiments. Open Grid Services Architecture Data Access and Integration (OGSA-DAI) is a good candidate to use as middleware providing access to several structured and semi-structured database products through Web/Grid services. The integration technique and its reference implementation described in this paper enable e-Scientists to reach databases via OGSA-DAI within their scientific workflows at run-time and give a general solution that can be adopted by any workflow management system.