2 research outputs found
Construction and Characterization of Protein-Encapsulated Electrospun Fibermats Prepared from a Silica/Poly(γ-glutamate) Hybrid
Protein-encapsulated fibermats are
an attractive platform for protein-based
bioactive materials. However, the choice of methods is still limited
and not applicable to a wide range of proteins. In this study, we
studied new polymeric materials for constructing protein-encapsulated
fibermats, in which protein molecules are encapsulated within the
nanofibers of fibermats without causing deleterious changes to protein
structure or function. We constructed a protein-encapsulated fibermat
using the poly(γ-glutamate) (PGA)/(3-glycidyloxypropyl)-trimethoxysilane
(GPTMS) hybrid as a precursor for electrospinning. Because the PGA/GPTMS
hybrid is water-soluble, protein molecules can be added to the precursor
in an aqueous solution, significantly enhancing protein stability.
Polycondensation during electrospinning (in-flight polycondensation)
makes the obtained fibermats water-insoluble, which stabilizes the
fibermat structure such that it is resistant to degradation in aqueous
buffer. The molecular structure of the PGA/GPTMS hybrid gives rise
to unique molecular permeability, which alters the selectivity and
specificity of biochemical reactions involving the encapsulated enzymes;
lower molecular-weight (MW) substrates can permeate the nanofibers,
promoting enzyme activity, but higher MW substrates such as inhibitor
peptides cannot permeate the nanofibers, suppressing enzyme activity.
We present an effective method of encapsulating bioactive molecules
while maintaining their structure and function, increasing the versatility
of electrospun fibermats for constructing various bioactive materials
Molecular Assembly of Zinc Chlorophyll Derivatives by Using Recombinant Light-Harvesting Polypeptides with His-tag and Immobilization on a Gold Electrode
LH1-α
and -β polypeptides, which make up the light-harvesting
1 (LH1) complex of purple photosynthetic bacteria, along with bacteriochlorophylls,
have unique binding properties even for various porphyrin analogs.
Herein, we used the porphyrin analogs, Zn-Chlorin and the Zn-Chlorin
dimer, and examined their binding behaviors to the LH1-α variant,
which has a His-tag at the C-terminus (MBP-rubα-YH). Zn-Chlorin
and the Zn-Chlorin dimer could bind to MBP-rubα-YH and form
a subunit-type assembly, similar to that from the native LH1 complex.
These complexes could be immobilized onto Ni-nitrilotriacetic acid-modified
Au electrodes, and the cathodic photocurrent was successfully observed
by photoirradiation. Since Zn-Chlorins in this complex are too far
for direct electron transfer from the electrode, a contribution of
polypeptide backbone for efficient electron transfer was implied.
These findings not only show interesting properties of LH1-α
polypeptides but also suggest a clue to construct artificial photosynthesis
systems using these peptide materials