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Volume 3, Issue 2
ISSN: 2470-9905
Crystallography 2017
October 16-17, 2017
2
nd
International Conference on
October 16-17, 2017 | Chicago, USA
Applied Crystallography
Precipitant-less crystallization of protein molecules induced by substrate with heterogeneous topography
and surface potential gradient
Anindita Sengupta Ghatak
and
Animangsu Ghatak
Indian Institute of Technology Kanpur, India
S
urfaces having heterogeneous topography are known to facilitate protein crystallization by diminishing the energy barrier for
nucleation. A precipitant is, nevertheless, required for shielding the charges on protein molecules, so that they can overcome
electrostatic repulsion and self-assemble into crystalline structure. For yet-to-be crystallized proteins, zeroing on the right precipitant
is a non-trivial problem and therefore, despite existence of several heterogeneous nucleant surfaces, number of proteins that are
yet to be crystallized continues to be large. In this talk, we will present a novel surface which is decorated with nanoscopic patterns
and also surface charges, the combined effect of which show the remarkable ability to induce crystallization without use of any
precipitant. This effect is demonstrated by crystallizing several protein molecules with molecular weight ranging from 14-450 kDa.
These surfaces are shown to induce also directed crystallization of a specific protein from a mixture of two or more protein species
and even simultaneous crystallization from a mixture of proteins. In essence, these surfaces consist of nanoscopic wrinkles with
spatially varying curvature and surface charges. Kelvin probe force microscopy (KPFM) measurements show that surface potential
gradient as high as 140 V/µm are generated on these surfaces which can drive largescale molecular ordering in the liquid at the
vicinity of the surface. As a result, the surface itself acts both as a precipitant also as a nucleant. Heterogeneity allows it to crystallize
protein molecules having large range of radius of gyration, that too at low to moderate concentration of the protein in respective
solutions. The prospect of precipitant-less crystallization of protein is expected to open up several possibilities in the areas of disease
diagnosis, drug discovery, drug delivery and protein engineering.
aghatak@iitk.ac.inStruct Chem Crystallogr Commun, 3:2
DOI: 10.21767/2470-9905-C1-003