the coiled coils in the design of protein-based constructs: hybrid hydrogels and epitope displays...
Post on 15-Jan-2016
214 views
TRANSCRIPT
The coiled coils in the design of protein-based constructs:
hybrid hydrogels and epitope displaysAijun Tang a , Chun Wang b, Russell J. Stewart b, Jindrich
Kopecek a ,b*
aDepartment of Pharmaceutics and Pharmaceutical Chemistry , 30S 2000E Rm. 301,University of Utah , Salt Lake City ,UT 84112,
USAbDepartment of Bioengineering , 20S 2030E Rm. 205,University of Utah , Salt Lake City
,UT 84112,USA
Published in Journal of Controlled Release 72(2001)
Introduction
Protein-based biomaterials and biomaterials with Proteins have been attracting more attention recently
Protein polymers contain mixtures of molecules with different chain length, lack of control of genetic engineering and chain architecture
Genetic Engineering made possible to produce peptide/protein with well defined amino acid sequence and precisely controlled macromolecular architectures including size, composition, sequence
Introduction
Genetic Engineering
Plasmid Technology
Engineered protein with non natural function
Produce new protein with predetermined properties
Conjugation of Polymer with genetically engineered site of protein for wide range purposes
Coiled Coils
A coiled coil is a bundle of two or more right-handed amphiphilic a-helices wrapping around each other into a slightly left-handed super-helix (Fig. 1A).
Consists of heptad repeats[(abcdefg)x]
a,d positions occupied by hydrophobic residues
The other positions usually occupied by polar ones
Hydrophobic interaction stabilizing the coiled coil conformation
Heterodimeric coiled coil used in biosensor and affinity purification
Coiled Coils
Parallel and antiparallel determined by electrostatic interaction between residues e and g
Affinity matrix for protein purification & Biosensor Application
Multivalent
Antibody
Conformationally defined synthetic lybray
Self replicating peptide
Coiled Coils
Design of hybrid hydrogels using coiled coil motif
Hydrogels are 3D polymer network that do not dissolve in water but are able to swell and retain significant amount of water, used in surgical sutures, soft tissue prostheses, drug delivery system, soft contact lenses
Old Tech Hydrogel
Lack exast control on 3D structure
Heterogeneity in structure and physicochemical properties
Hybrid hydrogel : hydrogel system contained two or more components of dinstinct classes of molecules
Design of hybrid hydrogels using coiled coil motif
Advantages of Hybrid hydrogel
We can combined good properties from different components to achieve a better one, example : assembling Hybrid hydrogel from synthetic polymers and Genetically engineered protein
It maybe possible to create HH that are responsive to a variety of stimuly such as ph, ionic strength, solvent, light, mechanical force, and specific ligand
Design of hybrid hydrogels using coiled coil motif
T increase
Design of an epitope display system usingcoiled coil motif
An epitope is the part of a macromolecule that is recognized by the immune system, specifically by antibodies, B cells, or cytotoxic T cells.
Small synthetic epitopes may represent a new category of targetting moieties for polymer based targettable drug delivery systems, but the problem is we need to find structure biorecognition relationship to achieve best targetting ability
BiomoleculesApplication
Biosensing
Affinity Separation
Generating surfaces with specific biocompatibility
Design of an epitope display system usingcoiled coil motif
Immobilization Technique
Physical Adsorption
Covalent Binding
Langmuir-Blodgett tech (LB) : popular for ordered monolayers of amphipiles
SAM
Alkanethiolate SAMs
Alkyl Siloxane SAMs
Design of an epitope display system usingcoiled coil motif
Biorecognition sites in proteins are often presented on the surfaces with the whole molecules serving as conformational scaffolds. To mimic natural proteins, protein/peptide construsts, such as coiled coil peptides, can be designed de novo and used a sequence simplified scaffolds into which recognition elements from naturally occuring proteins and peptides can be incorporated
Conclusions• Applying genetic engineering techniques to biomaterials and
drug delivery research offers numerous opportunities of creating protein based constructs with well-defined structure and unique properties
• Genetically engineered CCP motifs were used to form crosslinks of HH responsive to external stimuli
• Self Assembly CC stem loop constructs were prepared for studying the biorecognition between ligands and cell surface reseptors
• This approaches will lead to the development of intelligent drug delivery/release systems and will provide new insight for the rational design of more effective targetable drug carriers
THANK YOU