The methodologies of the directed evolution benefit from quantitative reading quantitatively genotype at the phenotype. We have therefore designed a method flowing from protein-peptide interactions to dynamic reading provided by a modified polymerase DNA. The melting of a processivity clamping protein on a polymerase thermostable nucleic acid allows a polymerase activity and an amplification of the DNA in high prohibition salt buffers. Here, we recap this phenotype by indirectly coupling the SSO7D processing clamp to the TAQ DNA polymerase via a respective fusion to a pair of high affinity peptide proteins and thermostable interaction. Escherichia coli cells co-expressing peptide-peptide-peptide pairs can be used directly in polymerase chain reactions to determine the relative interaction resistors by measuring amplic yields. The conditional activity of the polymerase is also used to connect the genotype to the phenotype of the interactive peptide pairs co-expressed in E. coli using the phased evolution platform for the compartmentalized automatic replication.
We validate this approach, called the replication with two hybrid compartmentalized, by selecting for the high affinity peptides that bind two models of model proteins: Spycacher and the large fragment of Nanoluc Luciferase. We demonstrate more co-evolution directed by hiking both protein and peptide components of the SpycCatcher-Spytag pair and by co-selecting for functional interactive variants. An important toxin-antitoxin (TA) HOK / Sok system, encoded by the plasmid R1 of Escherichia coli, is involved in the wake of post-segregation cells that have lost the plasmid. The deadly properties of HOK protein have been used for environmental containment of microbes and the development of potential vaccine candidates. We aim to demonstrate the powerful antimicrobial property of 19 fragment of the HOK peptide amino acid (AA) terminal.
This has been accomplished by designing a conditional suicide system based on HOK gene expression, cloned in an anhydroteracyclacin (ATC) inducible vector – PASK75. Thermal shocks and electroporation were used for the transformation of Escherichia coli cells and Vibrio Cholerae respectively. The minimum induction concentration (medium C) of the ATC, determined by analyzing the expression of the green fluorescent protein cloned separately in the PASK75 vector, was 30 ng / ml. As the HOK gene has been synthesized by Novo (using the reaction of the recombinant polymerase chain) in our study, various random size HOK fragments were generated (as a result of the possible nature of Taq. polymerase).
Building better DNA polymerases: Engineering Replication of Expanded Genetic Alphabets
DNA polymerases are now used in all scientific research, biotechnology and medicine, in part for their ability to interact with non-natural forms of DNA created by synthetic biologists. Here, especially, natural DNA polymerases often do not have “performance specifications” needed for processing technologies. This creates a need for rational (or semi-rational) scientific engineering engineering in order to identify variants that reproduce non-natural basic pairs (UBP), non-natural backbones, tags or other features evolutionually new from the Non-natural DNA. In this review, we provide a brief overview of the chemistry and properties of the replica DNA polymerases and their evolved variants, with a focus on the Klenow fragment of Taq DNA polymerase (Klentaq).
We describe studies of structural, enzymatic and comparative molecular dynamics of wild-type variants and klentaq, complex with natural or non-canonic substrates. The combination of these methods makes it possible to understand how the specific amino acid substitutions remote from the active site in a variant of the Klentaq DNA polymerase (ZP Klentaq) contribute to its ability to reproduce non-natural basic pairs (UBP). With improved efficiency compared to Klentaq. This approach can therefore be used to guide any future rational engineering of replicative DNA polymerases.
Directed co-evolution of interacting protein-peptide pairs by compartmentalized two-hybrid replication (C2HR)
Evaluation of the comparability of different methods of DNA extraction and amplification in microbial community profiling of intestines
Automated and broadband technologies are becoming increasingly common in microbiome studies to reduce costs and increase efficiency. However, in microbiome studies, small differences in methodology – including storage conditions, wet laboratory methods, sequencing platforms and data analysis – can affect the reproducibility and comparability of data between the studies.
The effects of broadband methods have been limited, including microfluidic PCR technologies. In this article, we compare two extraction methods (the mini Qiaamp DNA stool kit and the Mobio PowerSoil DNA insulation kit), two Taq polymerase enzymes (Mytaq HS Red Mix and Lock II PCR Tougymix) , two sets of primers (V3-V4 and V4 -V5) and two amplification methods (a two-step PCR protocol and a preparation of the amplicon library on the fluidigm access network system that allows multiplexing automated primers). The profiles of the Gut microbial community have been considerably affected by all variables. Although there has been no significant difference in alpha diversity measured between the two extraction methods, there was an effect of the extraction method on the community composition measured by unrestricted unifruc distances. The amplification method and primers have had a significant effect on alpha diversity and community composition.
Description: Polymerase Chain Reaction (PCR), invented by Kary B. Mullis, at the Cetus Corporation, who was awarded the 1993 Nobel Prize for chemistry for PCR, is a technique to exponentially amplify in vitro a small quantity of a specific nucleotide sequence using a thermostable (Taq) DNA polymerase. Anti-Taq Antibody is an ideal tool for hot-start PCR with Taq DNA polymerase. The Anti-Taq Antibody binds to Taq DNA polymerase and arrests the activity of Taq DNA Polymerase, preventing non-specific and primer dimer amplification resulted from non-specific priming at ambient temperature for the duration of time prior to PCR thermal cycling. During the initial denaturing step in PCR thermal cycling, the Anti-Taq Antibody is denatured and the Taq DNA polymerase is then released, thus regaining its full DNA polymerase activity. The result indicates that anti-Taq DNA Polymerase antibody increases the specificity and sensitivity of the PCR.
The relative abundance of actinobacteria was significantly lowered when using the Mobio Kit amplification method or fluidigm, and the relative abundance of firmoles was lower when using the Qiagen Kit. Microbial community profiles based on fluidigm-generated amplicon libraries have not been comparable to those generated by more commonly used methods. Researchers should carefully consider limitations and biases that different methods of extraction and amplification can introduce their results. In addition, a deeper benchmarking of automated methods and multiplexing is required to determine the magnitude of the potential compromise between the quality and the amount of data.
Jordan
