An Updated Overview of Protein Tags

Published April 23, 2019

Protein tagging has been around for decades, but their traditional uses are not frequent enough to make them common lab knowledge. Recent improvements in biochemical techniques have been increasing their frequency as creative design and analysis tools. In this overview, we offer a guide for the variety of different protein tags that are trending in recent growth.


This guide will cover:

  • Principle Affinity Tags
  • Biotin Tags
  • Epitope Tags
  • Fluorescent Tags

Principle Affinity Tags

Arg-tag
Overview
FunctionImmobilize functional proteins on flat surface
ApplicationStudying interactions with ligands
FeatureGFP with Arg-tag can be bound to mica surfaces
ApplicationScanning probe microscopy applications
Terminus AttachmentC-term
Compatible DomainBacterial
Measured Biochemistry
Purity95 %
Yield44 %
His-tag
Overview
FunctionImmobilization, linear recognition motif
ApplicationPurification (most common method)
FeatureStrongest interaction with immobilized metal ion matrice
ApplicationImmobilized metal-affinity chromatography (IMAC)
Terminus AttachmentN or C-terminal
Compatible DomainBacterial; Yeast; Mammalian; Viral
Measured Biochemistry
Purity95 %
Yield44 %
GST
Overview
FunctionIncreased solubility, highly antigenic
ApplicationPurification
FeatureAmplified detection
ApplicationProtein expression
Terminus AttachmentN or C-terminal

Biotin Tags

Strep-tag
Overview
FunctionMatrix regenerable, recognition motif
ApplicationPurification and detection
FeatureEukaryotic cell surface display, surface immobilization
ApplicationSPR CHIPS, NMR, Crystallization, Protein interactions
Terminus AttachmentN or C-terminal
Compatible DomainBacterial; Yeast; Mammalian; Insects; Plants; Synthetic
Streptavadin-tag
Overview
FunctionIncrease proteolytic stability, high affinity immobilization
ApplicationDetection and Expression support
FeatureNewer low affinity versions
ApplicationPurification
Terminus AttachmentN or C-terminal
Compatible DomainBacterial; Yeast; Mammalian; Insects; Plants; Synthetic

Epitope Tags

c-myc-tag
Overview
Function9E10 immunological recognition
ApplicationImmunoblotting/WB, Immunoprecipitation, Flow Cytometry
FeatureConvertible Reagent
ApplicationProtein engineering
Terminus AttachmentN or C-terminal
Compatible DomainBacterial; Yeast; Mammalian; Insects
FLAG-tag
Overview
FunctionPeptide bound to antibody (M1)
ApplicationPurification
FeatureConsistent non-denaturing conditions
ApplicationPurifying active fusion proteins
Terminus AttachmentN or C-terminal
Compatible DomainBacterial; Yeast; Mammalian
Measured Biochemistry
Purity90 %
HA-tag
Overview
FunctionViral antibody recognition
ApplicationDetection
FeatureAnti-HA antibodies specific
ApplicationExpression
Terminus AttachmentN or C-terminal
Compatible DomainMammalian
Measured Biochemistry
YieldLow

Fluorescent Tags

Luciferase
Overview
FunctionLuminescent dye
ApplicationDetection
FeatureServe as a reporter immediately upon translation
ApplicationIn-situ hybridization, RNA processing, RNA transfection
Terminus AttachmentN-terminal
Compatible DomainBacterial; Yeast; Mammalian; Insects
GFP
Overview
FunctionIntrinsic fluorescence can permit native detection
ApplicationDetection
FeatureNo antibody needed for detection
ApplicationMonitor gene expression, protein folding, and targeting
Terminus AttachmentN-terminal
Compatible DomainBacterial; Yeast; Mammalian; Insects
S-tag
Overview
FunctionSpecific linear recognition motif
ApplicationDetection
FeatureRNase S specificity
ApplicationDiverse assays; quantitative, colorimetric no antibody
Terminus AttachmentN or C-terminal
Compatible DomainBacterial; Yeast; Mammalian

Points to Consider

  1. FLAG mAb purification systems have not always been stable and often require expert intervention.
  2. The presence of C-terminal tags can potentially contribute to a protein's loss of function. Particularly in the case of enzymes.
  3. Streptavadin-binding peptide (SBP) is only attachable to the C-terminus
  4. S-tag in low pH elution may alter protein properties and limit the matrix reproducibility
  5. anti-myc antibody antibody purification is inconsistent and has been proven to result in poor yields

References

Nilsson et al. (1997a)
Lazzaroni et al. (1985)
Goldstein et al. (1992)
Crespo et al. (1997)
Makrides (1996)
McLean et al. (2001)
Nilsson et al. (1997b)
Wang et al. (1996)
Podbielski et al. (1992)
Jones et al. (1995)
Morandi et al. (1984)
Kaldalu et al. (2000)
Jones et al. (1995)
Rubinfeld et al. (1991)
Smith (2000)
Gerdes and Kaether (1996)
Los et al. (2008)
Terpe (2003)
Imagawa et al. (1982)
Fritze and Anderson (2000)
Tai et al. (1988)
Kuliopulos and Walsh (1994)
Kwatra et al. (1995)
Tai et al. (1988)
Karp and Oker-Blom (1999)
Kolodziej and Young (1991)
Terpe (2003)
Kimple and Sondek (2002)
Stevens (2000)
Bornhorst and Falke (2000)
Stevens (2000)
Abdulaev et al. (2005), Biao et al. (2004), Ruan et al. (2004)
Fritze and Anderson (2000)
Berlot (1999)
Nilsson et al. (1997b)
Skerra and Schmidt (2000)
Sano et al. (1998)
Terpe (2003)
Stevens (2000)
Li (2011)
Terpe (2003)
Nelson et al. (1999)