scholarly journals Electric-Field-Directed Self-Assembly of Active Enzyme-Nanoparticle Structures

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Alexander P. Hsiao ◽  
Michael J. Heller
Keyword(s):  
Electric Field ◽  
Self Assembly ◽  
Microelectrode Array ◽  
Glucose Sensor ◽  
Directed Assembly ◽  
Passive Layer ◽  
Higher Order ◽  
Significant Loss ◽  
Layer By Layer ◽  
Multilayered Structures

A method is presented for the electric-field-directed self-assembly of higher-order structures composed of alternating layers of biotin nanoparticles and streptavidin-/avidin-conjugated enzymes carried out on a microelectrode array device. Enzymes included in the study were glucose oxidase (GOx), horseradish peroxidase (HRP), and alkaline phosphatase (AP); all of which could be used to form a light-emitting microscale glucose sensor. Directed assembly included fabricating multilayer structures with 200 nm or 40 nm GOx-avidin-biotin nanoparticles, with AP-streptavidin-biotin nanoparticles, and with HRP-streptavidin-biotin nanoparticles. Multilayered structures were also fabricated with alternate layering of HRP-streptavidin-biotin nanoparticles and GOx-avidin-biotin nanoparticles. Results showed that enzymatic activity was retained after the assembly process, indicating that substrates could still diffuse into the structures and that the electric-field-based fabrication process itself did not cause any significant loss of enzyme activity. These methods provide a solution to overcome the cumbersome passive layer-by-layer assembly methods to efficiently fabricate higher-order active biological and chemical hybrid structures that can be useful for creating novel biosensors and drug delivery nanostructures, as well as for diagnostic applications.

Electric-Field-Directed Assembly of Biomolecular-Derivatized Nanoparticles into Higher-Order Structures

Small ◽  
2007 ◽  
Vol 3 (7) ◽  
pp. 1237-1244 ◽  
Author(s):  
Dietrich A. Dehlinger ◽  
Benjamin D. Sullivan ◽  
Sadik Esener ◽  
Michael J. Heller
Keyword(s):  
Electric Field ◽  
Directed Assembly ◽  
Higher Order ◽  
Order Structures

scholarly journals Structure of KAP1 tripartite motif identifies molecular interfaces required for retroelement silencing

2019 ◽  
Vol 116 (30) ◽  
pp. 15042-15051 ◽  
Author(s):  
Guido A. Stoll ◽  
Shun-ichiro Oda ◽  
Zheng-Shan Chong ◽  
Minmin Yu ◽  
Stephen H. McLaughlin ◽  
...  
Keyword(s):  
Self Assembly ◽  
Coiled Coil ◽  
Structural Data ◽  
Higher Order ◽  
Significant Loss ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Krab Domain ◽  
Genome Damage ◽  
Tripartite Motif

Transcription of transposable elements is tightly regulated to prevent genome damage. KRAB domain-containing zinc finger proteins (KRAB-ZFPs) and KRAB-associated protein 1 (KAP1/TRIM28) play a key role in regulating retrotransposons. KRAB-ZFPs recognize specific retrotransposon sequences and recruit KAP1, inducing the assembly of an epigenetic silencing complex, with chromatin remodeling activities that repress transcription of the targeted retrotransposon and adjacent genes. Our biophysical and structural data show that the tripartite motif (TRIM) of KAP1 forms antiparallel dimers, which further assemble into tetramers and higher-order oligomers in a concentration-dependent manner. Structure-based mutations in the B-box 1 domain prevent higher-order oligomerization without significant loss of retrotransposon silencing activity, indicating that, in contrast to other TRIM-family proteins, self-assembly is not essential for KAP1 function. The crystal structure of the KAP1 TRIM dimer identifies the KRAB domain binding site in the coiled-coil domain near the dyad. Mutations at this site abolished KRAB binding and transcriptional silencing activity of KAP1. This work identifies the interaction interfaces in the KAP1 TRIM responsible for self-association and KRAB binding and establishes their role in retrotransposon silencing.

Directed assembly of metal nanoparticles in polymer bilayers

2018 ◽  
Vol 3 (2) ◽  
pp. 390-396 ◽  
Author(s):  
Su-Wen Hsu ◽  
Yuhan Long ◽  
Aatheya G. Subramanian ◽  
Andrea R. Tao
Keyword(s):  
Metal Nanoparticles ◽  
Self Assembly ◽  
Directed Assembly ◽  
Nanocomposite Materials ◽  
Layer By Layer ◽  
Polymer Bilayers

The integration of layer-by-layer (LbL) and self-assembly methods has the potential to achieve precision assembly of nanocomposite materials.

Electric field-directed assembly of fullerene crystal rods into hierarchical films

2018 ◽  
Vol 6 (41) ◽  
pp. 11118-11127 ◽  
Author(s):  
Angela C. Stelson ◽  
Sonny J. Penterman ◽  
Chekesha M. Liddell Watson
Keyword(s):  
Electric Field ◽  
Material Properties ◽  
Self Assembly ◽  
Directed Assembly

Self-assembly of nanomaterials with desired material properties requires assembly control from nanometer to millimeter scales.

scholarly journals Structure of the tripartite motif of KAP1/TRIM28 identifies molecular interfaces required for transcriptional silencing of retrotransposons

2018 ◽  
Author(s):  
Guido A. Stoll ◽  
Shun-ichiro Oda ◽  
Zheng-Shan Chong ◽  
Minmin Yu ◽  
Stephen H. McLaughlin ◽  
...  
Keyword(s):  
Self Assembly ◽  
Coiled Coil ◽  
Transcriptional Silencing ◽  
Higher Order ◽  
Significant Loss ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Krab Domain ◽  
Tripartite Motif ◽  
Self Association

AbstractTranscription of transposable elements is tightly regulated to prevent damage to the genome. The family of KRAB domain-containing zinc finger proteins (KRAB-ZFPs) and KRAB-associated protein 1 (KAP1/TRIM28) play a key role in regulating retrotransposons. KRAB-ZFPs recognize specific retrotransposon sequences and recruit KAP1, which controls the assembly of an epigenetic silencing complex including histone H3K9 methyltransferase SETDB1. The chromatin remodeling activities of this complex repress transcription of the targeted transposable element and any adjacent genes. Here, we use biophysical and structural approaches to show that the tripartite motif (TRIM) of KAP1 forms antiparallel dimers, which further assemble into tetramers and higher-order oligomers in a concentration-dependent manner. Structure-based mutations in the B-box 1 domain prevented higher-order oligomerization without a significant loss of retrotransposon silencing activity in a cell-based assay, indicating that, in contrast to other TRIM family members, self-assembly is not essential for the function of KAP1. The crystal structure of the KAP1 RBCC dimer identifies the KRAB domain binding site, in the coiled-coil domain near the dyad. Mutations at this site abolished KRAB binding and transcriptional silencing activity of KAP1. This work identifies the interaction interfaces in the KAP1 RBCC motif responsible for self-association and KRAB binding and establishes their role in retrotransposon silencing.

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