1052 Citations
The cubic phase or in meso crystallization method is responsible for almost solved integral membrane protein structures Most of these are small and compact proteins A model for how crystals form by the in meso method has been proposed that invokes a transition between mesophases In light of this model we speculated that a more hydrated and open mesophase of reduced interfacial curvature would support facile crystallization of bigger and bulkier proteins The proposal was explored here by performing crystallization in the presence of additives that swell the cubic phase The additive concentration inducing swelling as quantified by small-angle X-ray ... More
The cubic phase or in meso crystallization method is responsible for almost 40 solved integral membrane protein structures. Most of these are small and compact proteins. A model for how crystals form by the in meso method has been proposed that invokes a transition between mesophases. In light of this model, we speculated that a more hydrated and open mesophase, of reduced interfacial curvature, would support facile crystallization of bigger and bulkier proteins. The proposal was explored here by performing crystallization in the presence of additives that swell the cubic phase. The additive concentration inducing swelling, as quantified by small-angle X-ray diffraction, coincided with a "crystallization window" in which two, very different transmembranal proteins produced crystals. That the swollen mesophase can grow structure-grade crystals was proven with one of these, the light-harvesting II complex. In most regards, the structural details of the corresponding complex resembled those of crystals grown by the conventional vapour diffusion method, with some important differences. In particular, packing density in the in meso-grown crystals was dramatically higher, more akin to that seen with water-soluble proteins, which accounts for their enhanced diffracting power. The layered and close in-plane packing observed has been rationalized in a model for nucleation and crystal growth by the in meso method that involves swollen mesophases. These results present a rational case for including mesophase-swelling additives in screens for in meso crystallogenesis. Their use will contribute to broadening the range of membrane proteins that yield to structure determination. Less
Protein crystallization is a difficult and time-consuming task because to obtain a crystal optimization steps are required almost systematically A tool that simplifies the optimization of crystallization conditions and that can be used by any crystallographer to design a crystallization plate and to visualize its content has become a paramount necessity A free and open-source application has been developed to automate this task It is based on a graphical user interface GUI that allows a personalized crystallization plate to be designed All data used and generated are saved in XML documents which allow reuse of the information The steps involved ... More
Protein crystallization is a difficult and time-consuming task, because to obtain a
crystal, optimization steps are required almost systematically. A tool that
simplifies the optimization of crystallization conditions, and that can be used by
any crystallographer to design a crystallization plate and to visualize its content,
has become a paramount necessity. A free and open-source application has been
developed to automate this task. It is based on a graphical user interface (GUI)
that allows a personalized crystallization plate to be designed. All data used and
generated are saved in XML documents, which allow reuse of the information.
The steps involved in preparing a crystallization plate and the functions of the
GUI designed to perform these steps are described. Plans for future
development are presented. The program was written in Java. The application
and its documentation are available under CeCILL license, which is a Free
Software license agreement. Less
crystal, optimization steps are required almost systematically. A tool that
simplifies the optimization of crystallization conditions, and that can be used by
any crystallographer to design a crystallization plate and to visualize its content,
has become a paramount necessity. A free and open-source application has been
developed to automate this task. It is based on a graphical user interface (GUI)
that allows a personalized crystallization plate to be designed. All data used and
generated are saved in XML documents, which allow reuse of the information.
The steps involved in preparing a crystallization plate and the functions of the
GUI designed to perform these steps are described. Plans for future
development are presented. The program was written in Java. The application
and its documentation are available under CeCILL license, which is a Free
Software license agreement. Less