The MoSGrid Science Gateway provides convenient ways to analyse and model threedimensional molecular structures using computational chemistry workflows. Molecular dynamics, quantum chemistry, and docking are the considered application domains. The science gateway including the data repository and underlying infrastructures was developed on top of the Liferay-based version of WS-PGRADE (Web services Parallel Grid Runtime and Developer Environment) using gUSE (grid User Support Environment), UNICORE, and XtreemFS technologies. The gateway allows users to seamlessly interact with the chemistry applications using data from the MoSGrid repository and running on Distributed Computing Infrastructures (DCIs). Data in the repository is centred on the Molecular Simulation Markup Language (MSML), which was developed in MoSGrid. For applications on the one hand and for analysis and visualization on the other hand format conversions from and to MSML are performed. Metadata, extracted from the MSML, is used to search the repository. The MoSGrid Science Gateway offers the use of data-centric workflows by integrating and extending a multitude of technologies. Users are enabled to run molecular computational simulations easily and efficiently with consistent data representations.