YASARA is a molecular-graphics, -modeling and -simulation program for Windows, Linux and Mac OS X developed since 1993, that finally makes it really easy to answer your questions. With an intuitive user interface, photorealistic graphics and support for affordable shutter glasses, autostereoscopic displays and input devices, YASARA creates a new level of interaction with the 'artificial reality', that allows you to focus on your goal and forget about the details of the program.

YASARA is powered by PVL (Portable Vector Language), a new development framework that provides performance way above traditional software . PVL allows you to visualize even the largest proteins and enables true interactive real-time simulations with highly accurate force fields on standard PCs (see benchmarks). You can push and pull molecules around and work with dynamic models instead of static pictures.

Being rooted in the academic world, all methods introduced by YASARA are described in peer-reviewed journals . You can obtain the initial stage 'YASARA View ' for free, while higher stages (YASARA Model, YASARA Dynamics , YASARA Structure) require a license fee that allows us to guarantee new developments, updates and support also in the future, independent of temporary grants. As a YASARA user, you are not limited to the role of a consumer. If you decide to share your developments with the community (macros, movies, Python plugins or just feedback), you receive credits that in turn give you free access to all stages of YASARA. Click here to see how others work with YASARA..

In addition to a wide range of functions that can partly also be found in other programs, YASARA provides a number of features with unique properties:

	Molecular graphics with GPU shaders and tessellation		Molecular movies and eLearning
	Molecular dynamics with 4 clicks		Interactive real-time surfaces
	New force fields: YASARA, YAMBER , NOVA		pH dependent typing of organic molecules
	Fastest molecular dynamics algorithms, see benchmarks		MD simulation of membrane proteins with 4 clicks
	Automatic force field parameter assignment for 98% of the PDB		Yanaconda macros and Python scripts
	Homology modeling with 4 clicks and CASP approval		Small-molecule docking with 4 clicks
	Loop modeling		Side-chain prediction
	pH dependent hydrogen bonding networks		Structure validation including ligands
	NMR structure determination with 4 clicks		Multi-dimensional knowledge-based potentials

With over 2000 citations, WHAT IF is a widely used modeling program, well known e.g. for its structure validation and prediction tools. The WHAT IF / YASARA Twinset is a unified all-in-one distribution of the two programs with extended functionality. If you run the Twinset WHAT IF,   an additional YASARA menu provides quick access to molecular simulations. And vice versa, users of the Twinset YASARA can simply run WHAT IF commands, so that WHAT IF inherits YASARA's user interface, graphics engine, macro language and convenience functions like unlimited undo/redo. This approach makes WHAT IF quickly accessible, also to users outside the bioinformatics expert community.