ChromoBlog

Introduction of Affinity vs. Specificity

Introduction

A high background from unspecific binding of proteins is a common problem in immunoprecipitation (IP). In this blog, the origin of background and different optimization strategies are discussed. Furthermore, it is shown how you can achieve a low background when using the ChromoTek GFP-Trap^®, a ready to use reagent for IP of a GFP-tagged proteins.

Estimated reading time:  3 minutes

The pull-down of proteins is an established technology. It can be difficult, particularly when the protein of interest is expressed at low levels. Here we discuss 5 tips that help you to improve your IP results.

Affinity tags are valuable tools for immunoprecipitation (IP). Fused to the protein of interest, they enable proteome-wide identification of interaction partners by mass spectrometry.

New iST Nano-Trap kits for immunoprecipitation (IP) and sample preparation for mass spectrometry (MS) in just 4 easy steps:

Introduction

Fluorescent proteins (FPs) have been used as protein tags since the mid-1990s mainly for cell biology and fluorescence microscopy. These tags have not only revolutionized cell biology by enabling the imaging of almost any protein, they are also used in biochemical applications. An important example is the immunoprecipitation and affinity purification of FP-tagged proteins, which was enabled by the development of affinity resins with high yield, purity, and affinity such as ChromoTek’s Nano-Traps (https://www.chromotek.com/products/detail/product-detail/nano-traps/).

In this blog we provide a review of

• green fluorescent proteins
• red fluorescent proteins
• self-labelling proteins, that require the covalent coupling of a fluorescent molecule

A collaboration between ChromoTek GmbH and Ludwig-Maximilians-University Munich (Germany) has yielded a novel nanobody that sheds new light on an important protein complex called INO80. This work was recently published in the high-impact journal Nature Structural & Molecular Biology (Knoll et al. 2018).

TurboGFP is a bright green fluorescent protein used to study protein function, localization and dynamics in cells. Nanobody based research tools allow reproducible biochemical analysis including mass spectrometry and enzyme activity measurements of TurboGFP fusion proteins.

Multiple literature references for GST-Trap

This article provides an overview of scientific publications that reference the ChromoTek GST-Trap superior binding performance for various applications. These include immunoprecipitation (IP), Co-IP of Glutathione S-Transferase (GST)-fusion proteins, and Luminex bead assays of GST-tagged and GFP-tagged proteins. Besides, usages for depletion of GST (glutathione sepharose)  after cleavage from recombinant fusion proteins and affinity purification of GST-tagged proteins are possible.