PlasmidMaker: a Versatile, Automated, and High Throughput End-to-End Platform for Plasmid Construction

Plasmids are used extensively in basic and applied biology. However, design and construction of plasmids, specifically the ones carrying complex genetic information, remains one of the most time-consuming, labor-intensive, and rate-limiting steps in performing sophisticated biological experiments. Here, we report the development of a versatile, robust, automated end-to-end platform named PlasmidMaker that allows error-free construction of plasmids with virtually any sequences in a high-throughput manner. This platform consists of a most versatile DNA assembly method using Pyrococcus furiosus Argonaute (PfAgo)-based artificial restriction enzymes, a user-friendly frontend for plasmid design, and a backend that streamlines the workflow and integration with a robotic system. As a proof of concept, we used this platform to generate 101 plasmids from six different species ranging from 5 to 18 kb in size from up to 11 DNA fragments within 3 days. PlasmidMaker should greatly expand the potential of synthetic biology.

In silico recombinant plasmid design of pHA171 with phdABCD insertion for ethidium bromide degradation

Background: Ethidium bromide is a common reagent that is used in nucleic acid staining. However, ethidium bromide has toxic and carcinogenic properties that are harmful to the environment. Phenanthrene dioxygenase (encoded by phdA, phdB, phdC, and phdD genes) in Nocardioides sp. KP7 can oxidize the phenanthridine structure aim to eliminate carcinogenic properties. Objective: This study aims to visualize and predict the structure, active site, and characteristics of the phenanthrene dioxygenase using bioinformatics tools. Methods: Plasmid design were prepared by inserting genes of interest phdA, phdB, phdC, and phdD from the NCBI database. Furthermore, several protein analysis tools were used for structure visualization, active site enzyme improvement, and protein characteristic of phenanthrene dioxygenase. Results: The prediction results found that phenanthrene dioxygenase reacts with the ethidium bromide substrate through the interaction of Fe3+ ions with water. The solubility level of phenanthrene dioxygenase protein is 0.404, suggesting that the protein has low solubility. The protein isoelectric point (pI) is between 5.17 to 5.36, and the protein molecular weight is 121.143 kDa. Conclusion: In silico analysis has supported that recombinant plasmid met characteristics for the construct which consists of gene interest and protein library.

Repository-based plasmid design Cost-optimal Gibson Assembly with repository DNA selection and primer generation

ABSTRACTThere was an explosion in the amount of commercially available DNA in sequence repositories over the last decade. The number of such plasmids increased from 12,000 to over 300,000 among three of the largest repositories: iGEM, Addgene, and DNASU. The challenge in biodesign remains how to use these and other repository-based sequences effectively, correctly, and seamlessly. This work describes an approach to plasmid design where a plasmid is specified as a DNA sequence or list of features. The proposed software then finds the most cost-effective combination of synthetic and PCR-prepared repository fragments to build the plasmid via Gibson Assembly. It finds existing DNA sequences in user-specified and public DNA databases: iGEM, Addgene, and DNASU. Such a software application is introduced and characterized against all post-2005 iGEM composite parts and all Addgene vectors submitted in 2018 and found to reduce costs by 34% versus a purely synthetic plasmid design approach. The described software will improve current plasmid assembly workflows by shortening design times, improving build quality, and reducing costs.