Transcript Presentation biomloecular

The coiled coils in the design of protein-based
constructs:
hybrid hydrogels and epitope displays
Aijun 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,
USA
bDepartment 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
Plasmid
Technology
Genetic
Engineering
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
Coiled Coils
Self replicating peptide
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
Lack exast control on 3D structure
Old Tech
Hydrogel
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 using
coiled 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
Biosensing
Biomolecules
Application
Affinity Separation
Generating surfaces with specific
Design of an epitope display system using
coiled coil motif
Physical Adsorption
Immobilization
Technique
Covalent Binding
Langmuir-Blodgett tech (LB) : popular for ordered monolayers of
amphipiles
Alkanethiolate SAMs
SAM
Alkyl Siloxane SAMs
Design of an epitope display system using
coiled 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
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