Protein Expression and Analysis
Working with Membrane Proteins: Tips for Expressing, Extracting, and Purifying Your Membrane Protein Sample
Working with membrane proteins can be tricky. Read on to get tried-and-tested tips and tricks for expressing, extracting, and purifying these water-phobic proteins.
Read More Constant Current or Voltage in SDS-PAGE: The Great Debate
It’s not always easy deciding whether to run electrophoresis at a constant voltage, current, or power. Here, we outline the differences to help you make an informed decision.
Read More IL-13 is a Pathogenic Driver of COVID-19
IL-13 is a Pathogenic Driver of COVID-19 Available On-Demand Speaker Alexandra Donlan Graduate StudentUniversity of Virginia Alexandra received her bachelor’s degree in Biological Sciences from Florida State University, where she studied the role of exosomes in the oncogenesis of Epstein–Barr virus in the lab of Dr David Meckes. She is working towards her PhD at…
Read More Development of ultrasensitive immunoassays for SARS-CoV-2 antibody detection
Development of ultrasensitive immunoassays for SARS-CoV-2 antibody detection Available On Demand Speaker Rosemary Sweetwood Manager, CAST Sample Testing, Scientist II CAST Custom Assay DevelopmentMilliporeSigma Rosemary Sweetwood has worked with SMC™ technology for over 7 years in diagnostic development, assay development, and custom manufacturing, as well as managing clinical sample testing projects for our SMC™ Sample…
Read More IgG Antibodies Against SARS-CoV-2 Correlate to Days from Symptom Onset in COVID-19 Positive Patients
IgG Antibodies Against SARS-CoV-2 Correlate to Days from Symptom Onset in COVID-19 Positive Patients Available On Demand Speaker Mary Young Research TechnicianUniversity of Virginia, School of Medicine Mary Young has her Bachelors of Science in Biology from Elon University. She joined the Petri Lab 3 years ago as a research technician helping with several projects,…
Read More Detecting Post-Translational Modifications
A-Z of Post-Translational Modifications
You might know the most common post-translational modifications, but there are many more than just phosphorylation and ubiquitination – come and test your knowledge!
Read More Synthetic Peptides and Their Uses: Part 1
Are you studying a small peptide or protein? Learn whether using synthetic peptides can save you hours of transfection, protein expression, and purification.
Read More An Experimental Toolkit for Measuring Autophagic Flux
How good is your cell at recycling? In this guide, we explain what autophagic flux is, why you need to study it, and methods to get you started.
Read More Top 5 Things to Keep in Mind When Detecting Non-Histone Lysine Acetylation
Lysine acetylation isn’t just for histones. Read on to find out how to determine whether your favorite protein is lysine acetylated.
Read More Recombinant Protein Expression: How to Choose the Right Affinity Tag
Using the right affinity tag can make protein purification a breeze. Read more to find out which tag is right for you.
Read More Immune Responses in Severe COVID-19 Patients
Speaker Professor Dexi Chen, the Director of the Beijing Institute of Hepatology, present data on immune responses in severe COVID-19.
Read More A Guide to Gradient Gels: The Why’s and How’s
Fret no more over fuzzy bands! We uncover how gradient gels can give you better results, and maximize your precious samples when performing SDS-PAGE
Read More Assay Development for Quantification of Low-abundance Proteins Using Single Molecule Counting
Assay Development for Quantification of Low-abundance Proteins Using Single Molecule Counting On-Demand Sponsored by Sarah HamrenMilliporeSigma In this tutorial you will find: How MilliporeSigma’s Single Molecule Counting (SMC™) platform can be used to detect even very low levels of Huntingtin protein How to reach fM levels of sensitivity detecting both mHTT and total HTT Development…
Read More Biology Beyond the Cell: the How and Why of Cell-Free Systems
Are your cell membranes more of a hindrance than a help? Struggling to sneak your DNA inside? Why not break out and take your expression or metabolism studies cell-free. Find out the what, how and why of cell-free systems.
Read More Fractionating Proteins by Solubility: or, How I Learned to Stop Worrying and Love the Ultracentrifuge
Does the term “ultracentrifuge” make your heart begin to race? Fear not! This article will provide you with tried and true tips on how to handle this piece of machinery like a boss.
Read More Icky Sticky: Heat Shock Protein Contamination during Protein Purification
Purifying a new protein is no easy feat. Finding combinations of protein purification buffer, salt, detergent, and stabilizing agent to get high yields of squeaky-clean protein can become tedious. Few things are as bothersome during this process as Heat Shock Protein (HSP) contamination. But worry not, we’ve got some handy tips to avoid HSP contamination…
Read More Spinning Around: Tips and Tricks for Using Centrifugal Filters
One of the most widespread protein laboratory accessories are the MWCO (molecular weight cut-off) centrifugal filters which are commonly used for concentrating protein, as well as DNA. They are available commercially with different cut-offs including 3kDa, 30kDa, 50kDa, 100kDa, and so on. These little devices are expensive and hence demand proper usage and care to…
Read More Laemmli Buffer: What Is It for Anyway?
Electrophoresis encompasses a wide range of techniques in which charged biomolecules in a liquid, a solid, or a semisolid solution can be separated by size under the application of an electric field. The most common application of electrophoresis for the separation of proteins is SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis), which has been previously covered here. …
Read More Designing a LOV2 Domain-Based Toolkit
Cell Biology is entering the Age of Light with a spectrum of new optogenetics tools available to control protein function using light. Once the remit of neuroscientists [1], the past decade has yielded a bounty of novel light-controllable domains that are now being leveraged to illuminate the dark corners of basic cell biology [2,3]. The…
Read More So You Think You Can PEMSA? A Guide to Protein Electrophoretic Mobility Shift Assay
Studying nucleic acid interactions with proteins can be accomplished using a rapid and efficient electrophoretic mobility shift assay (EMSA). This method is essentially an agarose gel electrophoresis technique that detects protein:nucleic acid interactions, as the mobility of the labeled nucleic acid will be retarded if bound to a protein (compared to unbound DNA). A lesser-known…
Read More The Mysterious World of Macrophages: How to Harness Them for Your Research
The Mysterious World of Macrophages: How to Harness Them for Your Research In this tutorial, you will learn: How to work with mouse and human macrophages The best methods for culturing macrophages The difference between M1 and M2 macrophages, and how to differentiate each population from monocytes What data to expect based on the conditions…
Read More How it Works: Storage Phosphor Screen
Radioactivity is still the most sensitive detection mechanism for many macromolecules and enzymatic activities. In graduate school, I performed countless radioactive kinase assays, watching the radioactive gamma 32P of ATP get transferred to my autophosphorylating receptor of interest, and then separating my protein from free hot ATP on a gel. The gel is dried, covered…
Read More 3 Ways to Use Flow Cytometry for Your Activation Experiment
Studying immune cell activation allows scientists to understand the way the body mounts a response to a specific infection, autoimmune diseases, or cancer. This knowledge plays a direct role in developing more efficacious vaccines and therapies. When tasked with capturing information on immune cell activation, flow cytometry remains the gold standard due to its versatility,…
Read More An Exploration of the Sigmoidal Curve – Math for the Rest of Us
ELISA (Enzyme-Linked Immunosorbent Assay) is the heartbeat of many labs in the research world, owing to its simplicity and its ability to answer a very basic question: how much of protein/peptide/antibody is in my sample? More specifically, it can be used to answer such questions as: How much IgG is in the serum after I…
Read More Will the Real NP-40 Please Stand Up? Chemical Nomenclature Woes.
One day, a colleague stopped by my workbench to ask which detergent would not break the nuclear membrane. Based on my previous experience using gentle detergents in lysis buffers, I replied, “NP-40”. However, we had two brands of NP-40. A closer look at the datasheets revealed that the chemical names were different even though they…
Read More How Protein Adhesion Can Affect Your Experiments and What to Do About It
Commonly, no one thinks much about how the surfaces of labware (like microcentrifuge tubes, test tubes, dishes, etc.) can affect experimental results. We might know when we need to use glass versus plastic. Or we might know that certain chemicals, like chloroform, will interact with some plastic polymers, and you must use polymers that are…
Read More Five Methods for Assessing Protein Purity and Quality
If you’ve ever worked with proteins in the lab, you probably know just how critical protein purity and quality are for downstream applications. In this article, we’ll review the multitude of problems that are encountered with ‘bad’ protein samples and how you can analyze the purity and integrity of your favorite protein prior to using…
Read More Let’s Come Clean: Why Quality Control for Purified Protein Matters
If you are a Michelin star chef, then your first priority for preparing your signature dish is to use the best ingredients. One rotten potato or one slightly overripe strawberry could ruin not just a dish, but also your reputation. In the laboratory we are (mostly) not cooking rotten potatoes, but we are doing delicate…
Read More 8 Tricks to Improve Your Negative Staining of Membrane Proteins
Negative staining of proteins is a versatile tool for structural biology. The sample preparation protocol is simple: the sample is embedded in a heavy metal stain that gives rise to increased specimen contrast. Thus, negative staining is a very convenient method to assess sample homogeneity, formation of macromolecular complexes, or quality of protein preparation. Conventional…
Read More A Beginner’s Guide to Measuring Metabolism In Vivo
Have you ever seen a mouse chowing down on its dinner and wondered how it translates to energy? Well, that’s exactly what is keeping some scientists up at night, and luckily these questions are now becoming easier to answer in quite significant detail. Over the last couple of decades, several companies have developed ‘metabolic cages’.…
Read More Crash Course: Developing a Fool-Proof ELISA
Crash Course: Developing a Fool-Proof ELISA Join us in this webinar featuring Dr. Omonse Talton who will guide you through developing a “fool proof” enzyme-linked immunosorbent assay (ELISA).In this tutorial, you will find: When and why you should use the different types of ELISAs– direct, indirect, sandwich, competitive/inhibition ELISA Major considerations for developing your ELISA…
Read More Crash Course in Fourier Transform Infrared Spectroscopy
Fourier transform infrared spectroscopy (FTIR) is an extremely sensitive technique for measuring the absorption and intensity of electromagnetic radiation in the infrared region of the spectrum of either a solid, liquid or gas sample. You can use FTIR to: quantify unknown compounds identify unknown compounds study the detailed structured coordination of compounds How Does Fourier…
Read More An Introduction to Chimeric Antigen Receptors (CARs)
You may have heard about a breakthrough cancer therapy that engineers patient’s immune cells to fight their cancer using chimeric antigen receptor (CAR)-T cells. If you don’t live in the world of immunology, you may not know what a CAR is, or what it is used for. Here you’ll find a brief guide to CARs,…
Read More Fishing for Kinases with Multiplex Inhibitor Bead Assays
There is something about kinases that resemble ghosts. Their effects reveal their presence, but they can be difficult to catch. With a low abundance of hundreds or even tens of molecules per cell, they are difficult to detect using conventional methods such as Western blotting or mass spectrometry (MS). However, you will need to detect…
Read More Top Five Methods for Primary Antibody Labeling
In any application that uses antibodies for signal detection (e.g., Western blotting, ELISA, immunohistochemistry, or FACS), there are two approaches to antibody labeling: direct and indirect labeling. Standard Western blotting uses indirect labeling because you use a primary antibody to detect the target antigen, followed by a secondary antibody to which a detection molecule is…
Read More An Experimental Tool-kit for Measuring Protein Stability
Proteins in the cell are in a constant flux governed by events including synthesis and degradation. In an effort to make cells more efficient by reducing the unnecessary protein load, most proteins in the cell have a specifically defined half-life. Another reason why cells have evolved to degrade proteins is to ensure timely removal of…
Read More Helpful Tips Before Your First Rho Pull-Down Assay
If you have studied cellular movement or cell division, you have encountered Rho in the literature, because it regulates both processes. And the list of roles for Rho in the cell continues to grow! The prominence of Rho in the biology of non-diseased and diseased cells has caused researchers to continually optimize the Rho pull-down…
Read More Navigating the “Cs” Part 1: an Introduction to Chromatin Conformation Capture Techniques
Interest in the three-dimensional structure of chromatin has exploded over the past few years—and for good reason! We now know that DNA isn’t randomly piled into the nucleus like a bowl of spaghetti, but arranged in functional loops and domains, more like a city blueprint. This is particularly exciting to (epi)genomic scientists, because 3D chromatin…
Read More Troubleshooting a Faulty ELISA
Is ELISA giving you the blues? The frustrating kind, not the lovely kind you get while watching the enzyme substrate reaction! This age old assay has the perks of being quick and fairly simple to perform, but when conditions are not perfect, ELISAs can deliver less than optimal results, and fail to be consistent and…
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