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56996
SARS-CoV-2 Spike Protein (S1-NTD) Antibody
Primary Antibodies
Polyclonal Antibody

SARS-CoV-2 Spike Protein (S1-NTD) Antibody #56996

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  1. WB
  2. IP
Western Blotting Image 1: SARS-CoV-2 Spike Protein (S1-NTD) Antibody

Western blot analysis of extracts from mock-infected Vero-E6 cells (lane 1) and SARS-CoV-2-infected Vero-E6 cells (lane 2), using SARS-CoV-2 Spike Protein (S1-NTD) Antibody (upper) and GAPDH (D16H11) XP® Rabbit mAb #5174 (lower). The antibody detects full-length (uncleaved) SARS-CoV-2 spike protein, and the fragment corresponding to the S1 domain generated by endogenous protease cleavage. Vero-E6 cells courtesy of Dr. Mohsan Saeed, National Emerging Infectious Diseases Laboratories, Boston University.

Western Blotting Image 2: SARS-CoV-2 Spike Protein (S1-NTD) Antibody

Western blot analysis of SARS-CoV-2 Spike S1-NTD (16-316) Recombinant Protein (8xHis-Tag) #88587 (lane 1), SARS-CoV-2 Spike (trimeric) (16-1208) Recombinant Protein (8xHis-Tag) #65444 (lane 2), SARS-CoV-2 Spike RBD (318-541) Recombinant Protein (8xHis-Tag) #48801 (lane 3), or SARS-CoV-2 Spike RBD (multimeric) (319-591) Recombinant Protein (8xHis-Tag) #17862 (lane 4), using SARS-CoV-2 Spike Protein (S1-NTD) Antibody (upper) and His-Tag (D3I1O) XP® Rabbit mAb #12698 (lower). Due to the location of the epitope (surrounding Pro25 of SARS-CoV-2 spike protein), the antibody detects recombinant proteins corresponding to the full-length ectodomain and the S1-NTD of SARS CoV-2 spike protein but does not detect recombinant proteins corresponding only to the receptor binding domain (RBD).

Western Blotting Image 3: SARS-CoV-2 Spike Protein (S1-NTD) Antibody

Western blot analysis of extracts from 293T cells, mock transfected (lane 1) or transiently transfected with expression constructs encoding Myc/DDK-tagged SARS-CoV-2 spike (lane 2), Myc/DDK-tagged SARS-CoV spike (lane 3), or Myc/DDK-tagged MERS-CoV spike (lane 4), using SARS-CoV-2 Spike Protein (S1-NTD) Antibody (upper), Myc-Tag (71D10) Rabbit mAb #2278 (middle), and GAPDH (D16H11) XP® Rabbit mAb #5174 (lower). The antibody detects full-length (uncleaved) SARS-CoV-2 spike protein, and the fragment corresponding to the S1 domain generated by endogenous protease cleavage. Proteolytic cleavage of SARS-CoV spike is not observed in these experimental conditions (transient transfection).

Immunoprecipitation Image 1: SARS-CoV-2 Spike Protein (S1-NTD) Antibody

Immunoprecipitation of SARS-CoV-2 spike protein from extracts of 293T cells transiently transfected with an expression construct encoding SARS-CoV-2 spike protein. Lane 1 is 10% input, lane 2 is Normal Rabbit IgG #2729, and lane 3 is SARS-CoV-2 Spike Protein (S1-NTD) Antibody. Western blot analysis was performed using SARS-CoV-2 Spike Protein (S1-NTD) (E7M5X) Mouse mAb #42172. Anti-mouse IgG, HRP-linked Antibody #7076 was used as the secondary antibody.

To Purchase # 56996S
Product # Size Price
56996S
100 µl $ 276

Supporting Data

REACTIVITY Vir
SENSITIVITY Endogenous
MW (kDa) 110, 220
SOURCE Rabbit

Application Key:

  • W-Western
  • IP-Immunoprecipitation
  • IHC-Immunohistochemistry
  • ChIP-Chromatin Immunoprecipitation
  • IF-Immunofluorescence
  • F-Flow Cytometry
  • E-P-ELISA-Peptide

Species Cross-Reactivity Key:

  • H-Human
  • M-Mouse
  • R-Rat
  • Hm-Hamster
  • Mk-Monkey
  • Vir-Virus
  • Mi-Mink
  • C-Chicken
  • Dm-D. melanogaster
  • X-Xenopus
  • Z-Zebrafish
  • B-Bovine
  • Dg-Dog
  • Pg-Pig
  • Sc-S. cerevisiae
  • Ce-C. elegans
  • Hr-Horse
  • All-All Species Expected

Product Usage Information

Application Dilution
Western Blotting 1:1000
Immunoprecipitation 1:50

Storage

Supplied in 10 mM sodium HEPES (pH 7.5), 150 mM NaCl, 100 µg/ml BSA and 50% glycerol. Store at –20°C. Do not aliquot the antibody.

Protocol

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Western Blotting Protocol

For western blots, incubate membrane with diluted primary antibody in 5% w/v nonfat dry milk, 1X TBS, 0.1% Tween® 20 at 4°C with gentle shaking, overnight.

NOTE: Please refer to primary antibody product webpage for recommended antibody dilution.

A. Solutions and Reagents

NOTE: Prepare solutions with reverse osmosis deionized (RODI) or equivalent grade water.

  1. 20X Phosphate Buffered Saline (PBS): (#9808) To prepare 1 L 1X PBS: add 50 ml 20X PBS to 950 ml dH2O, mix.
  2. 10X Tris Buffered Saline (TBS): (#12498) To prepare 1 L 1X TBS: add 100 ml 10X to 900 ml dH2O, mix.
  3. 1X SDS Sample Buffer: Blue Loading Pack (#7722) or Red Loading Pack (#7723) Prepare fresh 3X reducing loading buffer by adding 1/10 volume 30X DTT to 1 volume of 3X SDS loading buffer. Dilute to 1X with dH2O.
  4. 10X Tris-Glycine SDS Running Buffer: (#4050) To prepare 1 L 1X running buffer: add 100 ml 10X running buffer to 900 ml dH2O, mix.
  5. 10X Tris-Glycine Transfer Buffer: (#12539) To prepare 1 L 1X Transfer Buffer: add 100 ml 10X Transfer Buffer to 200 ml methanol + 700 ml dH2O, mix.
  6. 10X Tris Buffered Saline with Tween® 20 (TBST): (#9997) To prepare 1 L 1X TBST: add 100 ml 10X TBST to 900 ml dH2O, mix.
  7. Nonfat Dry Milk: (#9999).
  8. Blocking Buffer: 1X TBST with 5% w/v nonfat dry milk; for 150 ml, add 7.5 g nonfat dry milk to 150 ml 1X TBST and mix well.
  9. Wash Buffer: (#9997) 1X TBST.
  10. Primary Antibody Dilution Buffer: 1X TBST with 5% nonfat dry milk; for 20 ml, add 1.0 g nonfat dry milk to 20 ml 1X TBST and mix well.
  11. Biotinylated Protein Ladder Detection Pack: (#7727).
  12. Blue Prestained Protein Marker, Broad Range (11-250 kDa): (#59329).
  13. Blotting Membrane and Paper: (#12369) This protocol has been optimized for nitrocellulose membranes. Pore size 0.2 µm is generally recommended.
  14. Secondary Antibody Conjugated to HRP: Anti-rabbit IgG, HRP-linked Antibody (#7074).
  15. Detection Reagent: SignalFire™ ECL Reagent (#6883).

B. Protein Blotting

A general protocol for sample preparation.

  1. Treat cells by adding fresh media containing regulator for desired time.
  2. Aspirate media from cultures; wash cells with 1X PBS; aspirate.
  3. Lyse cells by adding 1X SDS sample buffer (100 µl per well of 6-well plate or 500 µl for a 10 cm diameter plate). Immediately scrape the cells off the plate and transfer the extract to a microcentrifuge tube. Keep on ice.
  4. Sonicate for 10–15 sec to complete cell lysis and shear DNA (to reduce sample viscosity).
  5. Heat a 20 µl sample to 95–100°C for 5 min; cool on ice.
  6. Microcentrifuge for 5 min.
  7. Load 20 µl onto SDS-PAGE gel (10 cm x 10 cm).

    NOTE: Loading of prestained molecular weight markers (#59329, 10 µl/lane) to verify electrotransfer and biotinylated protein ladder (#7727, 10 µl/lane) to determine molecular weights are recommended.

  8. Electrotransfer to nitrocellulose membrane (#12369).

C. Membrane Blocking and Antibody Incubations

NOTE: Volumes are for 10 cm x 10 cm (100 cm2) of membrane; for different sized membranes, adjust volumes accordingly.

I. Membrane Blocking

  1. (Optional) After transfer, wash nitrocellulose membrane with 25 ml TBS for 5 min at room temperature.
  2. Incubate membrane in 25 ml of blocking buffer for 1 hr at room temperature.
  3. Wash three times for 5 min each with 15 ml of TBST.

II. Primary Antibody Incubation

  1. Incubate membrane and primary antibody (at the appropriate dilution and diluent as recommended in the product webpage) in 10 ml primary antibody dilution buffer with gentle agitation overnight at 4°C.
  2. Wash three times for 5 min each with 15 ml of TBST.
  3. Incubate membrane with Anti-rabbit IgG, HRP-linked Antibody (#7074 at 1:2000) and Anti-biotin, HRP-linked Antibody (#7075 at 1:1000–1:3000) to detect biotinylated protein markers in 10 ml of blocking buffer with gentle agitation for 1 hr at room temperature.
  4. Wash three times for 5 min each with 15 ml of TBST.
  5. Proceed with detection (Section D).

D. Detection of Proteins

Directions for Use:

  1. Wash membrane-bound HRP (antibody conjugate) three times for 5 minutes in TBST.
  2. Prepare 1X SignalFire™ ECL Reagent (#6883)by diluting one part 2X Reagent A and one part 2X Reagent B (e.g. for 10 ml, add 5 ml Reagent A and 5 ml Reagent B). Mix well.
  3. Incubate substrate with membrane for 1 minute, remove excess solution (membrane remains wet), wrap in plastic and expose to X-ray film.

* Avoid repeated exposure to skin.

posted June 2005

revised June 2020

Protocol Id: 263

Immunoprecipitation for Native Proteins

This protocol is intended for immunoprecipitation of native proteins for analysis by western immunoblot or kinase activity utilizing Protein A magnetic separation.

A. Solutions and Reagents

NOTE: Prepare solutions with reverse osmosis deionized (RODI) or equivalent grade water.

  1. 20X Phosphate Buffered Saline (PBS): (#9808) To prepare 1 L of 1X PBS, add 50 ml 20X PBS to 950 ml dH2O, mix.
  2. 10X Cell Lysis Buffer: (#9803) To prepare 10 ml of 1X cell lysis buffer, add 1 ml cell lysis buffer to 9 ml dH2O, mix.

    NOTE: Add 1 mM PMSF (#8553) immediately prior to use.

  3. 3X SDS Sample Buffer: Blue Loading Pack (#7722) or Red Loading Pack (#7723) Prepare fresh 3X reducing loading buffer by adding 1/10 volume 30X DTT to 1 volume of 3X SDS loading buffer.
  4. Protein A Magnetic Beads: (#73778).
  5. Magnetic Separation Rack: (#7017) or (#14654).
  6. 10X Kinase Buffer (for kinase assays): (#9802) To Prepare 1 ml of 1X kinase buffer, add 100 µl 10X kinase buffer to 900 µl dH2O, mix.
  7. ATP (10 mM) (for kinase assays): (#9804) To prepare 0.5 ml of ATP (200 µM), add 10 µl ATP (10 mM) to 490 µl 1X kinase buffer.

B. Preparing Cell Lysates

  1. Aspirate media. Treat cells by adding fresh media containing regulator for desired time.
  2. To harvest cells under nondenaturing conditions, remove media and rinse cells once with ice-cold 1X PBS.
  3. Remove PBS and add 0.5 ml ice-cold 1X cell lysis buffer to each plate (10 cm) and incubate on ice for 5 min.
  4. Scrape cells off the plate and transfer to microcentrifuge tubes. Keep on ice.
  5. Sonicate on ice three times for 5 sec each.
  6. Microcentrifuge for 10 min at 4°C, 14,000 x g and transfer the supernatant to a new tube. The supernatant is the cell lysate. If necessary, lysate can be stored at -80°C.

C. Immunoprecipitation

Cell Lysate Pre-Clearing (Optional)

A cell lysate pre-clearing step is highly recommended to reduce non-specific protein binding to the Protein A Magnetic beads. Pre-clear enough lysate for test samples and isotype controls.

  1. Briefly vortex the stock tube to resuspend the magnetic beads.

    IMPORTANT: Pre-wash #73778 magnetic beads just prior to use:

  2. Transfer 20 μl of bead slurry to a clean tube. Place the tube in a magnetic separation rack for 10-15 seconds.

    Carefully remove the buffer once the solution is clear. Add 500 μl of 1X cell lysis buffer to the magnetic bead pellet, briefly vortex to wash the beads. Place tube back in magnetic separation rack. Remove buffer once solution is clear. Repeat washing step once more.

  3. Add 200 μl cell lysate to 20 μl of pre-washed magnetic beads.

    IMPORTANT: The optimal lysate concentration will depend on the expression level of the protein of interest. A starting concentration between 250 μg/ml-1.0 mg/ml is recommended.

  4. Incubate with rotation for 20 minutes at room temperature.
  5. Separate the beads from the lysate using a magnetic separation rack, transfer the pre-cleared lysate to a clean tube, and discard the magnetic bead pellet.
  6. Proceed to immunoprecipitation section.

Immunoprecipitation

IMPORTANT: Appropriate isotype controls are highly recommended in order to show specific binding in your primary antibody immunoprecipitation. Use Normal Rabbit IgG #2729 for rabbit polyclonal primary antibodies, Rabbit (DA1E) mAb IgG XP® Isotype Control #3900 for rabbit monoclonal primary antibodies, and Mouse (G3A1) mAb IgG1 Isotype Control #5415 for mouse monoclonal primary antibodies. Isotype controls should be concentration matched and run alongside the primary antibody samples

  1. Add primary antibody (at the appropriate dilution as recommended in the product datasheet) to 200 µl cell lysate. Incubate with rotation overnight at 4°C. to form the immunocomplex.
  2. Pre-wash magnetic beads (see Cell Lysate Pre-Clearing section, steps 1 and 2).
  3. Transfer the lysate and antibody (immunocomplex) solution to the tube containing the pre-washed magnetic bead pellet.
  4. Incubate with rotation for 20 min at room temperature.
  5. Pellet beads using magnetic separation rack. Wash pellets five times with 500 μl of 1X cell lysis buffer. Keep on ice between washes.
  6. Proceed to analyze by western immunoblotting or kinase activity (section D).

D. Sample Analysis

Proceed to one of the following specific set of steps.

For Analysis by Western Immunoblotting

  1. Resuspend the pellet with 20-40 µl 3X SDS sample buffer, briefly vortex to mix, and briefly microcentrifuge to pellet the sample.
  2. Heat the sample to 95-100°C for 5 min.
  3. Pellet beads using magnetic separation rack. Transfer the supernatant to a new tube. The supernatant is the sample.
  4. Analyze sample by western blot (see Western Immunoblotting Protocol).

NOTE: To minimize masking caused by denatured IgG heavy chains (~50 kDa), we recommend using Mouse Anti-Rabbit IgG (Light-Chain Specific) (D4W3E) mAb (#45262) or Mouse Anti-Rabbit IgG (Conformation Specific) (L27A9) mAb (#3678) (or HRP conjugate #5127). To minimize masking caused by denatured IgG light chains (~25 kDa), we recommend using Mouse Anti-Rabbit IgG (Conformation Specific) (L27A9) mAb (#3678) (or HRP conjugate #5127).

For Analysis by Kinase Assay

  1. Wash pellet twice with 500 µl 1X kinase buffer. Keep on ice.
  2. Suspend pellet in 40 µl 1X kinase buffer supplemented with 200 µM ATP and appropriate substrate.
  3. Incubate for 30 min at 30°C.
  4. Terminate reaction with 20 µl 3X SDS sample buffer. Vortex, then microcentrifuge for 30 sec.
  5. Transfer supernatant containing phosphorylated substrate to another tube.
  6. Heat the sample to 95-100°C for 2-5 min and microcentrifuge for 1 min at 14,000 x g.
  7. Load the sample (15-30 µl) on SDS-PAGE gel.

posted December 2008

revised April 2018

Protocol Id: 410

Specificity / Sensitivity

SARS-CoV-2 Spike Protein (S1-NTD) Antibody recognizes endogenous levels of total SARS-CoV-2 spike protein. This antibody detects full-length protein, and also detects the S1 fragment generated by furin cleavage. It does not cross-react with spike proteins from SARS or MERS coronaviruses.

Species Reactivity:

Virus

Source / Purification

Polyclonal antibodies are produced by immunizing animals with a synthetic peptide corresponding to residues surrounding Pro25 of SARS-CoV-2 spike protein. Antibodies are purified by peptide affinity chromatography.

Background

The cause of the COVID-19 pandemic is a novel and highly pathogenic coronavirus, termed SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2). SARS-CoV-2 is a member of the Coronaviridae family of viruses (1). The genome of SARS-CoV-2 is similar to other coronaviruses, and is comprised of four key structural proteins: S, the spike protein, E, the envelope protein, M, the membrane protein, and N, the nucleocapsid protein (2). Coronavirus spike proteins are class I fusion proteins and harbor an ectodomain, a transmembrane domain, and an intracellular tail (3,4). The highly glycosylated ectodomain projects from the viral envelope surface and facilitates attachment and fusion with the host cell plasma membrane. The ectodomain can be further subdivided into host receptor-binding domain (RBD) (S1) and membrane-fusion (S2) subunits, which are produced upon proteolysis by host proteases at S1/S2 and S2’ sites. S1 and S2 subunits remain associated after cleavage and assemble into crown-like homotrimers (2,4). In humans, both SARS-CoV and SARS-CoV-2 spike proteins utilize the angiotensin-converting enzyme 2 (ACE2) protein as a receptor for cellular entry (5-7). Spike protein subunits represent a key antigenic feature of coronavirus virions, and therefore represent an important target of vaccines, novel therapeutic antibodies, and small-molecule inhibitors (8,9).

  1. Zhou, P. et al. (2020) Nature 579, 270-3.
  2. Tortorici, M.A. and Veesler, D. (2019) Adv Virus Res 105, 93-116.
  3. Li, F. et al. (2006) J Virol 80, 6794-800.
  4. Li, F. (2016) Annu Rev Virol 3, 237-61.
  5. Shang, J. et al. (2020) Nature 581, 221-4.
  6. Wrapp, D. et al. (2020) Science 367, 1260-3.
  7. Yan, R. et al. (2020) Science 367, 1444-8.
  8. Yuan, Y. et al. (2017) Nat Commun 8, 15092.
  9. Amanat, F. and Krammer, F. (2020) Immunity 52, 583-9.

Pathways & Proteins

Explore pathways + proteins related to this product.

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