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| Targets |
GroEL chaperonin. The GroES mobile loop binds to the apical domain of GroEL, a chaperonin involved in protein folding. GroES is a heptameric co-chaperonin that, together with GroEL, forms a cage for substrate protein folding. The mobile loop of each GroES subunit (approximately 16 amino acids) is responsible for the interaction with GroEL. In free GroES, the loop is highly flexible and disordered, but upon binding to GroEL, it folds into a defined beta-hairpin structure, with a hydrophobic tripeptide (e.g., I/L/V-x-x) physically interacting with hydrophobic residues on GroEL's apical domain. This interaction is essential for GroEL-GroES complex formation, ATP hydrolysis, and substrate protein encapsulation. The peptide is not a drug but a research tool; it does not directly inhibit GroEL but serves as a model for the binding interface.
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| ln Vitro |
GroES mobile loop is a very adaptable portion of free GroES that attaches to GroEL via the loop's tip residues.
In vitro, the GroES mobile loop peptide binds to GroEL with high affinity, mimicking the interaction between the full-length GroES heptamer and GroEL. Binding studies have demonstrated that the synthetic peptide (corresponding to residues 13-32 or 19-27 of E. coli GroES) adopts a characteristic bulged beta-hairpin conformation when bound to GroEL, as shown by transferred NOE (nuclear Overhauser effect) NMR experiments. The peptide inhibits the ability of GroES to support GroEL-mediated protein folding in a concentration-dependent manner, by competitively blocking the GroES binding site on GroEL. In chaperonin assays, the peptide prevents the formation of the functional GroEL-GroES complex, thereby disrupting protein folding and refolding of denatured substrates (e.g., rhodanese or GFP). The peptide is also used as a model for studying disorder-to-order transitions in protein-protein interactions. It does not have enzymatic activity but rather acts as a ligand or inhibitor of GroEL in biochemical assays. |
| ln Vivo |
Not applicable (research reagent, not a drug). The GroES mobile loop peptide is not administered to animals as a therapeutic agent and is not used in in vivo efficacy studies. It is a biochemical research tool primarily used in in vitro systems (test tubes, purified proteins, or cell lysates) to study chaperonin function. Some researchers may use the peptide as a control or as a tool to perturb GroEL function in cell-based assays by microinjection or transfection, but this is uncommon. No in vivo activity data are available for this peptide. For ex vivo use, the peptide can be added to tissue homogenates or cell extracts to study its effects on protein aggregation or folding. However, it is not a drug candidate and has no approved therapeutic indications.
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| Enzyme Assay |
For a direct binding assay between the GroES mobile loop peptide and GroEL, surface plasmon resonance (SPR) is the preferred method. Purified GroEL (E. coli) is immobilized onto a CM5 sensor chip via amine coupling (EDC/NHS chemistry) or captured via an anti-His antibody if His-tagged GroEL is used. The GroES mobile loop peptide (sequence: ETKSAGGIVLTGS or a longer 13-32 residue peptide) is dissolved in running buffer (10 mM HEPES pH 7.4, 150 mM NaCl, 3 mM EDTA, 0.005% P20, 1 mM DTT). Increasing concentrations of peptide (0.1-1000 uM) are flowed over the immobilized GroEL at 25degC at a flow rate of 30 uL/min. Association (2-3 min) and dissociation (5-10 min) phases are recorded. The sensorgrams are double-referenced (subtracting reference channel and buffer blank). The KD (dissociation constant) is calculated by fitting the data to a steady-state affinity model or a 1:1 Langmuir binding model using BIAevaluation or similar software. For a fluorescence-based binding assay: GroEL is labeled with a fluorophore (e.g., fluorescein or Alexa Fluor). The peptide, when bound, may cause a change in fluorescence intensity or anisotropy. Alternatively, a competitive binding assay can be performed: a known GroEL-binding peptide (e.g., a fluorescently labeled GroES loop peptide) is used as a tracer, and its binding to GroEL is competed by increasing concentrations of unlabeled GroES mobile loop peptide. Fluorescence polarization (FP) is measured after incubation for 30-60 minutes at room temperature. IC50 is determined, and Ki is calculated using the Cheng-Prusoff equation. For a pull-down assay (in vitro protein-protein interaction): Biotinylated GroES mobile loop peptide (biotin-peptide) is immobilized on streptavidin-agarose beads. Purified GroEL (1-10 ug) is incubated with the beads in binding buffer (50 mM Tris-HCl pH 7.5, 100 mM KCl, 5 mM MgCl2, 1 mM DTT, 0.1% BSA) for 1-2 hours at 4degC with gentle rotation. After washing, bound GroEL is eluted, separated by SDS-PAGE, and detected by Coomassie staining or immunoblotting with anti-GroEL antibody.
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| Cell Assay |
For cell-based assays that examine the effects of the GroES mobile loop peptide on protein folding, E. coli cells (or other bacterial systems) can be used. The peptide is not cell-permeable; therefore, it is typically used in cell lysates or permeabilized cells. For a cell lysate-based protein refolding assay: E. coli cells are lysed in lysis buffer (50 mM Tris-HCl pH 7.5, 5 mM MgCl2, 50 mM KCl, 1 mM DTT, 1 mM ATP), and the soluble fraction is obtained by centrifugation. Denatured model substrate (e.g., rhodanese or luciferase) is diluted into the lysate in the presence of increasing concentrations of GroES mobile loop peptide (0.1-1000 uM). After incubation at 37degC for 15-60 min, the recovery of enzymatic activity (e.g., rhodanese activity measured by colorimetric assay; luciferase activity measured by luminescence) is assessed. The peptide is expected to inhibit chaperonin-mediated refolding in a dose-dependent manner. For live-cell imaging of protein aggregation: E. coli cells expressing a temperature-sensitive substrate (e.g., GFP fused to an aggregation-prone protein) are treated with cell-penetrating peptide conjugates of GroES mobile loop (if conjugated to a CPP), or cells are permeabilized (e.g., with lysozyme/EDTA). After treatment, fluorescence microscopy is used to assess protein aggregation patterns. However, most applications are in vitro (purified components) rather than live-cell assays due to lack of cell permeability. All experiments should include a scrambled sequence peptide as a negative control and a known chaperonin inhibitor (e.g., benzyl alcohol) as a positive control.
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| Animal Protocol |
Not applicable. The GroES mobile loop peptide is a research tool for in vitro biochemical studies and is not administered to animals. Therefore, in vivo animal experiment protocols for this peptide as a therapeutic agent are not available. The peptide may be used ex vivo: after administering a drug or disease model induction in animals, tissues (e.g., brain, liver) are harvested, lysed, and the lysates are incubated with the peptide to study its effects on protein aggregation or GroEL-like chaperone function in the tissue. However, such studies are very rare. The peptide is not intended for in vivo use because it does not cross cell membranes (unless conjugated to a cell-penetrating peptide or formulated in a delivery vehicle). No published animal efficacy studies using the naked GroES mobile loop peptide exist. For researchers needing to study the role of GroEL/ES in bacterial infection models, genetic approaches (e.g., GroES knockdown or overexpression) are more appropriate than peptide-based methods. The GroES mobile loop peptide is strictly a laboratory reagent.
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| ADME/Pharmacokinetics |
No pharmacokinetic (PK) data are available for the GroES mobile loop peptide. As a 13-16 amino acid peptide (MW ~1.2-1.5 kDa), it would be rapidly cleared from the circulation if administered intravenously, with a plasma half-life of a few minutes due to glomerular filtration and proteolytic degradation by serum and tissue peptidases. The peptide does not cross the blood-brain barrier (BBB) or cell membranes due to its size and hydrophilicity. The peptide is not intended for in vivo administration; it is used exclusively in in vitro or ex vivo biochemical assays. Therefore, PK parameters such as absorption, distribution, metabolism, excretion (ADME), bioavailability, half-life, and clearance are not relevant or reported. For research that requires intracellular delivery, conjugation to a cell-penetrating peptide (CPP) (e.g., TAT, penetratin) or encapsulation in liposomes may be considered, but such modifications would alter the PK profile. In its unmodified form, the peptide is not an in vivo tool.
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| Toxicity/Toxicokinetics |
No toxicity data are available for the GroES mobile loop peptide. As a short peptide consisting of naturally occurring L-amino acids, the GroES mobile loop peptide is generally considered to have low toxicity. In vitro, the peptide is not cytotoxic to bacterial or mammalian cells at concentrations up to 1 mM, as assessed by cell viability assays. Since the peptide is not cell-permeable, it does not enter cells to interfere with intracellular chaperonin function under standard culture conditions. For use in lysates or purified systems, the peptide poses no toxicity risk to researchers when handled with standard laboratory safety precautions (gloves, lab coat, eye protection). The peptide is typically supplied as a lyophilized powder or TFA salt; the TFA counterion is present in low amounts and is considered non-toxic. The peptide is not intended for human or animal use and has not been evaluated in toxicology studies. No genotoxicity, carcinogenicity, organ toxicity, or reproductive toxicity data exist. Standard laboratory hygiene practices are sufficient for safe handling.
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| References | |
| Additional Infomation |
The GroEL-GroES chaperonin system is essential for protein folding in E. coli and other bacteria. GroEL is a large, double-ring chaperonin that binds misfolded proteins, and GroES is a heptameric co-chaperonin that caps the GroEL ring, creating an isolated "Anfinsen cage" in which protein folding can occur safely. The GroES mobile loop (approximately 16 residues) is the key structural element that mediates GroEL binding and undergoes a transition from a random coil in free GroES to a well-defined beta-hairpin when bound to GroEL. The peptide sequence is highly conserved among bacterial species and eukaryotic mitochondrial homologs. GroES mobile loop peptide is a synthetic peptide representing this loop (typically residues 13-32 or 19-27 of the E. coli GroES sequence: ETKSAGGIVLTGS). The peptide is not a drug, and it is not approved for therapeutic use. It is a research-grade biochemical tool for studying chaperonin function, protein folding, and protein-protein interactions. The peptide is also used in NMR and X-ray crystallography to determine the structure of the GroEL-GroES interface. The peptide is for research use only, not for clinical or therapeutic applications.
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| Molecular Formula |
C51H90N14O20
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| Molecular Weight |
1219.34
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| Appearance |
White to off-white solid powder
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| HS Tariff Code |
2934.99.9001
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| Storage |
Powder -20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month Note: Please store this product in a sealed and protected environment, avoid exposure to moisture. |
| Shipping Condition |
Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)
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| Solubility (In Vitro) |
H2O :~33.33 mg/mL (~27.33 mM)
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| Solubility (In Vivo) |
Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.
Injection Formulations
Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)(e.g. IP/IV/IM/SC) *Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution. Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil) Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals). View More
Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)] Oral Formulations
Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium) Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals). View More
Oral Formulation 3: Dissolved in PEG400 (Please use freshly prepared in vivo formulations for optimal results.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 0.8201 mL | 4.1006 mL | 8.2012 mL | |
| 5 mM | 0.1640 mL | 0.8201 mL | 1.6402 mL | |
| 10 mM | 0.0820 mL | 0.4101 mL | 0.8201 mL |
*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.
Calculation results
Working concentration： mg/mL；
Method for preparing DMSO stock solution： mg drug pre-dissolved in μL DMSO (stock solution concentration mg/mL). Please contact us first if the concentration exceeds the DMSO solubility of the batch of drug.
Method for preparing in vivo formulation:：Take μL DMSO stock solution, next add μL PEG300, mix and clarify, next addμL Tween 80, mix and clarify, next add μL ddH2O，mix and clarify.
(1) Please be sure that the solution is clear before the addition of next solvent. Dissolution methods like vortex, ultrasound or warming and heat may be used to aid dissolving.
(2) Be sure to add the solvent(s) in order.
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