Nature applies enzymatic assembly lines to synthesize bioactive compounds. Inspired by such capabilities, we have developed a facile method for spatially segregating attached enzymes in a continuous-flow, vortex fluidic device (VFD). Fused Hisn-tags at the protein termini allow rapid bioconjugation and consequent purification through complexation with immobilized metal affinity chromatography (IMAC) resin. Six proteins were purified from complex cell lysates to average homogeneities of 76%. The most challenging to purify, tobacco epi-aristolochene synthase, was purified in only ten minutes from cell lysate to near homogeneity (>90%). Furthermore, this “reaction-ready” system demonstrated excellent stability during five days of continuous-flow. Towards multi-step transformations in continuous flow, proteins were arrayed as ordered zones on the reactor surface allowing segregation of catalysts. Ordering enzymes into zones opens new opportunities for continuous flow biosynthesis.
The COVID-19 pandemic has resulted in over two million deaths worldwide. Despite efforts to fight the virus, the disease continues to overwhelm hospitals with severely ill patients.
Proteases cut with enviable precision and regulate diverse molecular events in biology. Such qualities drive a seemingly inexhaustible appetite for proteases with new activities and capabilities. Comprising 25% of the total industrial enzyme market, proteases appear in consumer goods, such as detergents, textile processing, and numerous foods; additionally, proteases include 25 US Food and Drug Administration-approved medicines and various research tools. Recent advances in protease engineering strategies address target specificity, catalytic efficiency, and stability. This guide to protease engineering surveys best practices and emerging strategies. We further highlight gaps and flexibilities inherent to each system that suggest opportunities for new technology development along with engineered proteases to solve challenges in proteomics, protein sequencing, and synthetic gene circuits.
GUIDING PROTEASE CHOICE AND ITS EVOLUTION WITH BIOINFORMATICS AND OTHER DATAIndependent of the desired outcome, all protease engineering strategies begin by choosing an appropriate starting enzyme, typically through bioinformatics searches (Figure 2). The ideal ll
A polymer-based electrode capable of specific detection of human serum albumin, and its glycated derivatives, is described. The sensor is constructed from a glass microscope slide coated with a synthesized, polythiophene film bearing a protected, iminodiacetic acid motif. The electrode surface is then further elaborated to a functional biosensor through deprotection of the iminodiacetic acid, followed by metal-affinity immobilization of a specific and high-affinity, albumin ligand. Albumin was then quantified in buffer and synthetic urine via electrochemical impedance spectroscopy. Glycated albumin was next bound to a boronic acid-modified, singlecysteine dihydrofolate reductase variant to quantify glycation ratios by square-wave voltammetry. The platform offers high sensitivity, specificity, and reproducibility in an inexpensive arrangement. The detection limits exceed the requirements for intermediate-term glycemic control monitoring in diabetes patients at 5 and 1 nM for albumin and its glycated forms, respectively.
Characterization of antibody response to SARS-CoV-2 is urgently needed to predict COVID-19 disease trajectories. Ineffective antibodies or antibody-dependent enhancement (ADE) could derail patient immune responses, for example. ELISA and coronavirus antigen microarray (COVAM) analysis epitope-mapped plasma from 86 COVID-19 patients. The experiments identified antibodies to a 21-residue epitope from nucleocapsid (termed Ep9) associated with severe disease, including ICU stay, requirement for ventilators, and death. Furthermore, anti-Ep9 antibodies correlate both with various comorbidities and ADE hallmarks, including increased IL-6 levels and early IgG response. Importantly, anti-Ep9 antibodies can be detected within five days post-symptom onset and sometimes within one day. The results lay the groundwork for a new type of COVID-19 diagnostic for the early prediction of disease severity to guide more effective therapeutic interventions.
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