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Article: Rapid Quantification of Monoclonal Antibody Titer in Cell Culture Harvests by Antibody-Induced Z-ELP-E2 Nanoparticle Cross-Linking

Swartz, Andrew R / Wilfred Chen

Analytical chemistry. 2018 Nov. 24, v. 90, no. 24

2018

Abstract: Existing assays for the quantification of monoclonal antibody (mAb) cell culture titer often require expensive instruments or reagents and may be limited by the low-throughput or tedious protocols. Here, we developed a quick and cost-effective ... ...

Abstract	Existing assays for the quantification of monoclonal antibody (mAb) cell culture titer often require expensive instruments or reagents and may be limited by the low-throughput or tedious protocols. Here, we developed a quick and cost-effective alternative assay based on mAb-induced cross-linking with Z-domain-ELP-E2 nanocages functionalized by SpyTag/SpyCatcher conjugation. After mixing mAb samples with a fixed nanoparticle concentration for 10 min, we found that the turbidity, measured by absorbance at 600 nm, exhibited a high-signal-to-background ratio and was proportional to the mAb concentration. A simple logarithmic regression was found to fit (R2 = 0.99) the turbidity data for mAb concentrations between 100 and 1000 μg/mL. The optimized assay procedure was validated using two industrial mAb cell culture harvests, and a bridging study using Octet biolayer interferometry with Protein A sensors confirmed accurate and reproducible results. The assay procedure can be easily adapted to a high-throughput format for rapid mAb titer screening.
Keywords	absorbance ; cell culture ; cost effectiveness ; crosslinking ; interferometry ; mixing ; monoclonal antibodies ; nanoparticles ; screening ; turbidity
Language	English
Dates of publication	2018-1124
Size	p. 14447-14452.
Publishing place	American Chemical Society
Document type	Article
ZDB-ID	1508-8
ISSN	1520-6882 ; 0003-2700
ISSN (online)	1520-6882
ISSN	0003-2700
DOI	10.1021/acs.analchem.8b04083
Database	NAL-Catalogue (AGRICOLA)

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Article: A non-chromatographic protein purification strategy using Src 3 homology domains as generalized capture domains

Kim, Heejae / Wilfred Chen

Journal of biotechnology. 2016 Sept. 20, v. 234

2016

Abstract: Protein purification using inverse phase transition of elastin-like polypeptide (ELP) domains is a useful alternative to chromatography. Genetic fusions of ELP domains to various proteins have the ability to reversibly transition between soluble monomers ...

Abstract	Protein purification using inverse phase transition of elastin-like polypeptide (ELP) domains is a useful alternative to chromatography. Genetic fusions of ELP domains to various proteins have the ability to reversibly transition between soluble monomers and micron-sized aggregates and this has been used to selectively purify many ELP fusions. Affinity domains can enhance this technology by using specific protein binding domains to enable ELP mediated affinity capture (EMAC) of proteins of interest (POI) that have been fused to corresponding affinity ligands. In this paper, we highlight the use of Src homology 3 (SH3) domains and corresponding peptide ligands in EMAC that have differential binding affinities towards SH3 for efficient capture and elution of proteins. Furthermore, differences between capture and elution of a monomeric and a multimeric protein were also studied.
Keywords	binding capacity ; binding proteins ; chromatography ; ligands ; phase transition ; polypeptides ; sequence homology
Language	English
Dates of publication	2016-0920
Size	p. 27-34.
Publishing place	Elsevier B.V.
Document type	Article
ZDB-ID	843647-2
ISSN	1873-4863 ; 0168-1656 ; 1389-0352
ISSN (online)	1873-4863
ISSN	0168-1656 ; 1389-0352
DOI	10.1016/j.jbiotec.2016.07.016
Database	NAL-Catalogue (AGRICOLA)

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Zs.A 2299: Show issues

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Article: HaloTag mediated artificial cellulosome assembly on a rolling circle amplification DNA template for efficient cellulose hydrolysis

Sun, Qing / Wilfred Chen

Chemical communications. 2016 May 10, v. 52, no. 40

2016

Abstract: We report here the generation of four-component artificial cellulosomes onto a DNA scaffold using the self-labeling HaloTag for DNA conjugation. The resulting structures exhibited significantly improved cellulosome assembly as well as cellulose ... ...

Abstract	We report here the generation of four-component artificial cellulosomes onto a DNA scaffold using the self-labeling HaloTag for DNA conjugation. The resulting structures exhibited significantly improved cellulosome assembly as well as cellulose hydrolysis over compatible structures generated using protein scaffolds. Cellulose hydrolysis was further enhanced by 2-fold using the more complex cellulosome structures assembled onto DNA templates generated by rolling circle amplification (RCA). The flexibility to insert additional hybridization sites in a multiplexing manner using RCA should enable the assembly of a larger array of cellulases to better mimic the enzyme diversity of naturally occurring cellulosomes.
Keywords	DNA ; artificial membranes ; cellulases ; cellulose ; cellulosome ; chemical compounds ; hydrolysis ; scaffolding proteins
Language	English
Dates of publication	2016-0510
Size	p. 6701-6704.
Publishing place	The Royal Society of Chemistry
Document type	Article
ZDB-ID	1472881-3
ISSN	1364-548X ; 1359-7345 ; 0009-241X
ISSN (online)	1364-548X
ISSN	1359-7345 ; 0009-241X
DOI	10.1039/c6cc02035f
Database	NAL-Catalogue (AGRICOLA)

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Article: DNA-guided assembly of a five-component enzyme cascade for enhanced conversion of cellulose to gluconic acid and H2O2

Chen, Qi / Nosang Myung / Sooyoun Yu / Wilfred Chen

Journal of biotechnology. 2017,

2017

Abstract: Enzymatic fuel cells have received considerable attention because of their potential for direct conversion of abundant raw materials such as cellulose to electricity. The use of multi-enzyme cascades is particularly attractive as they offer the ... ...

Abstract	Enzymatic fuel cells have received considerable attention because of their potential for direct conversion of abundant raw materials such as cellulose to electricity. The use of multi-enzyme cascades is particularly attractive as they offer the possibility of achieving a series of complex reactions at higher efficiencies. Here we reported the use of a DNA-guided approach to assemble a five-component enzyme cascade for direct conversion of cellulose to gluconic acid and H2O2. Site-specific co-localization of Î²-glucosidase and glucose oxidase resulted in over 11-fold improvement in H2O2 production from cellobiose, highlighting the benefit of substrate channeling. Although a more modest 1.5-fold improvement in H2O2 production was observed using a five-enzyme cascade, due to H2O2 inhibition on enzyme activity, these results demonstrated the possibility to enhance the production of gluconic acid and H2O2 directly from cellulose by DNA-guided enzyme assembly.
Keywords	beta-glucosidase ; cellobiose ; cellulose ; electricity ; enzyme activity ; fuel cells ; gluconic acid ; glucose oxidase ; hydrogen peroxide ; raw materials
Language	English
Size	p. .
Publishing place	Elsevier B.V.
Document type	Article
Note	Pre-press version
ZDB-ID	843647-2
ISSN	1873-4863 ; 0168-1656 ; 1389-0352
ISSN (online)	1873-4863
ISSN	0168-1656 ; 1389-0352
DOI	10.1016/j.jbiotec.2017.10.006
Database	NAL-Catalogue (AGRICOLA)

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Article: Engineering the bioconversion of methane and methanol to fuels and chemicals in native and synthetic methylotrophs

Bennett, R Kyle / Lisa M Steinberg / Wilfred Chen / Eleftherios T Papoutsakis

Elsevier Ltd Current opinion in biotechnology. 2018 Apr., v. 50

2018

Abstract: Methylotrophy describes the ability of organisms to utilize reduced one-carbon compounds, notably methane and methanol, as growth and energy sources. Abundant natural gas supplies, composed primarily of methane, have prompted interest in using these ... ...

Abstract	Methylotrophy describes the ability of organisms to utilize reduced one-carbon compounds, notably methane and methanol, as growth and energy sources. Abundant natural gas supplies, composed primarily of methane, have prompted interest in using these compounds, which are more reduced than sugars, as substrates to improve product titers and yields of bioprocesses. Engineering native methylotophs or developing synthetic methylotrophs are emerging fields to convert methane and methanol into fuels and chemicals under aerobic and anaerobic conditions. This review discusses recent progress made toward engineering native methanotrophs for aerobic and anaerobic methane utilization and synthetic methylotrophs for methanol utilization. Finally, strategies to overcome the limitations involved with synthetic methanol utilization, notably methanol dehydrogenase kinetics and ribulose 5-phosphate regeneration, are discussed.
Keywords	anaerobic conditions ; biotransformation ; energy ; engineering ; methane ; methanol ; methanotrophs ; natural gas ; ribulose
Language	English
Dates of publication	2018-04
Size	p. 81-93.
Publishing place	Elsevier Ltd
Document type	Article
ZDB-ID	1052045-4
ISSN	1879-0429 ; 0958-1669
ISSN (online)	1879-0429
ISSN	0958-1669
DOI	10.1016/j.copbio.2017.11.010
Database	NAL-Catalogue (AGRICOLA)

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Article ; Online: Microbial Biosensors

Miso Park / Shen-Long Tsai / Wilfred Chen

Sensors, Vol 13, Iss 5, Pp 5777-

Engineered Microorganisms as the Sensing Machinery

2013 Volume 5795

Abstract: Whole-cell biosensors are a good alternative to enzyme-based biosensors since they offer the benefits of low cost and improved stability. In recent years, live cells have been employed as biosensors for a wide range of targets. In this review, we will ... ...

Abstract	Whole-cell biosensors are a good alternative to enzyme-based biosensors since they offer the benefits of low cost and improved stability. In recent years, live cells have been employed as biosensors for a wide range of targets. In this review, we will focus on the use of microorganisms that are genetically modified with the desirable outputs in order to improve the biosensor performance. Different methodologies based on genetic/protein engineering and synthetic biology to construct microorganisms with the required signal outputs, sensitivity, and selectivity will be discussed.
Keywords	synthetic biology ; scaffolds ; genetic circuits ; Chemical technology ; TP1-1185
Language	English
Publishing date	2013-05-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article: Bactericidal activity of elastin-like polypeptide biopolymer with polyhistidine domain and silver

Krishnani, Kishore K / Ashok Mulchandani / Wilfred Chen

Colloids and Surfaces B: Biointerfaces. 2014 July 01, v. 119

2014

Abstract: In the present study, elastin-like biopolymer (ELP) composed of a polyhistidine domain has been investigated as a silver binding agent for antibacterial activity against Escherichia coli, a model test strain for Gram-negative bacteria for antibacterial ... ...

Abstract	In the present study, elastin-like biopolymer (ELP) composed of a polyhistidine domain has been investigated as a silver binding agent for antibacterial activity against Escherichia coli, a model test strain for Gram-negative bacteria for antibacterial assays of nanoparticles, and Vibrio harveyi, an opportunistic pathogen which cause mass mortality in shrimp Penaeus monodon reared in coastal aquaculture. The concentration dependent antimicrobial activity of ELPH-Ag on E. coli and V. harveyi was examined by agar well diffusion method and further confirmed through growth curves using spectrophotometer assisted absorption observations. The increased concentrations of ELP-Ag effectively checked the bacterial growth and increased the diameter of inhibition zone. The results showed a minimum inhibitory concentration of 37Î¼g/ml. This study has an application in formulating artificial protein based antibacterial in diverse fields of healthcare and management of disease in coastal aquaculture.
Keywords	absorption ; agar ; antibacterial properties ; antibiotics ; binding agents ; biopolymers ; colloids ; disease control ; Escherichia coli ; Gram-negative bacteria ; mariculture ; microbial growth ; minimum inhibitory concentration ; mortality ; nanoparticles ; pathogens ; Penaeus monodon ; polypeptides ; shrimp ; silver ; spectrophotometers ; Vibrio harveyi
Language	English
Dates of publication	2014-0701
Size	p. 66-70.
Publishing place	Elsevier B.V.
Document type	Article
ZDB-ID	1500523-9
ISSN	1873-4367 ; 0927-7765
ISSN (online)	1873-4367
ISSN	0927-7765
DOI	10.1016/j.colsurfb.2014.03.018
Database	NAL-Catalogue (AGRICOLA)

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Article ; Online: Positional assembly of enzymes on bacterial outer membrane vesicles for cascade reactions.

Miso Park / Qing Sun / Fang Liu / Matthew P DeLisa / Wilfred Chen

PLoS ONE, Vol 9, Iss 5, p e

2014 Volume 97103

Abstract: The systematic organization of enzymes is a key feature for the efficient operation of cascade reactions in nature. Here, we demonstrate a facile method to create nanoscale enzyme cascades by using engineered bacterial outer membrane vesicles (OMVs) that ...

Abstract	The systematic organization of enzymes is a key feature for the efficient operation of cascade reactions in nature. Here, we demonstrate a facile method to create nanoscale enzyme cascades by using engineered bacterial outer membrane vesicles (OMVs) that are spheroid nanoparticles (roughly 50 nm in diameter) produced by Gram-negative bacteria during all phases of growth. By taking advantage of the fact that OMVs naturally contain proteins found in the outer cell membrane, we displayed a trivalent protein scaffold containing three divergent cohesin domains for the position-specific presentation of a three-enzyme cascade on OMVs through a truncated ice nucleation protein anchoring motif (INP). The positional assembly of three enzymes for cellulose hydrolysis was demonstrated. The enzyme-decorated OMVs provided synergistic cellulose hydrolysis resulting in 23-fold enhancement in glucose production than free enzymes.
Keywords	Medicine ; R ; Science ; Q
Language	English
Publishing date	2014-01-01T00:00:00Z
Publisher	Public Library of Science (PLoS)
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article: Synthetic scaffolds for pathway enhancement

Siu, Ka-Hei / Long Chen / Qing Sun / Rebecca P Chen / Shen-Long Tsai / Wilfred Chen

Current opinion in biotechnology. 2015 Dec., v. 36

2015

Abstract: Controlling local concentrations of reactants, intermediates, and enzymes in synthetic pathways is critical for achieving satisfactory productivity of any desired products. An emerging approach to exert control over local concentrations is the use of ... ...

Abstract	Controlling local concentrations of reactants, intermediates, and enzymes in synthetic pathways is critical for achieving satisfactory productivity of any desired products. An emerging approach to exert control over local concentrations is the use of synthetic biomolecular scaffolds to co-localize key molecules of synthetic pathways. These scaffolds bring the key molecules into close proximity by recruiting pathway enzymes via ligand binding and/or physically sequestrating enzymes and metabolites into isolated compartments. Novel scaffolds made of proteins, nucleic acids, and micro-compartments with increasingly complex architecture have recently been explored and applied to a variety of pathways, with varying degrees of success. Despite these strides, precise assembly of synthetic scaffolds remains a difficult task, particularly in vivo, where interactions both intended and unexpected can lead to unpredictable results. Additionally, because heterologous enzymes often have lowered activities in their new hosts, an ideal scaffold should provide a flexible platform that can adapt to kinetic imbalances in different contexts. In this review, we discuss some of the notable advances in the creation of these synthetic scaffolds and highlight the current challenges in their application.
Keywords	enzymes ; hosts ; ligands ; metabolites ; nucleic acids ; proteins
Language	English
Dates of publication	2015-12
Size	p. 98-106.
Publishing place	Elsevier Ltd
Document type	Article
ZDB-ID	1052045-4
ISSN	1879-0429 ; 0958-1669
ISSN (online)	1879-0429
ISSN	0958-1669
DOI	10.1016/j.copbio.2015.08.009
Database	NAL-Catalogue (AGRICOLA)

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Article ; Online: Biosensor for Direct Determination of Fenitrothion and EPN Using Recombinant Pseudomonas putida JS444 with Surface Expressed Organophosphorus Hydrolase. 1. Modified Clark Oxygen Electrode

Ashok Mulchandani / Wilfred Chen / Priti Mulchandani / Yu Lei

Sensors, Vol 6, Iss 4, Pp 466-

2006 Volume 472

Abstract: This paper reports a first microbial biosensor for rapid and cost-effectivedetermination of organophosphorus pesticides fenitrothion and EPN. The biosensorconsisted of recombinant PNP-degrading/oxidizing bacteria Pseudomonas putida JS444anchoring and ... ...

Abstract	This paper reports a first microbial biosensor for rapid and cost-effectivedetermination of organophosphorus pesticides fenitrothion and EPN. The biosensorconsisted of recombinant PNP-degrading/oxidizing bacteria Pseudomonas putida JS444anchoring and displaying organophosphorus hydrolase (OPH) on its cell surface asbiological sensing element and a dissolved oxygen electrode as the transducer. Surface-expressed OPH catalyzed the hydrolysis of fenitrothion and EPN to release 3-methyl-4-nitrophenol and p-nitrophenol, respectively, which were oxidized by the enzymaticmachinery of Pseudomonas putida JS444 to carbon dioxide while consuming oxygen,which was measured and correlated to the concentration of organophosphates. Under theoptimum operating conditions, the biosensor was able to measure as low as 277 ppb offenitrothion and 1.6 ppm of EPN without interference from phenolic compounds and othercommonly used pesticides such as carbamate pesticides, triazine herbicides andorganophosphate pesticides without nitrophenyl substituent. The applicability of thebiosensor to lake water was also demonstrated.
Keywords	Organophosphorus ; fenitrothion ; EPN ; biosensor ; Pseudomonas putida. ; Technology (General) ; T1-995 ; Technology ; T ; DOAJ:Technology (General) ; DOAJ:Technology and Engineering ; Analytical chemistry ; QD71-142 ; Chemistry ; QD1-999 ; Science ; Q ; DOAJ:Analytical Chemistry ; DOAJ:Chemistry
Subject code	540
Language	English
Publishing date	2006-04-01T00:00:00Z
Publisher	MDPI AG
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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