Bid BH3 (80-99), FAM labeled

Product Name: Bid BH3 (80-99), FAM labeled

Sequence One Letter Code: 5-FAM-EDIIRNIARHLAQVGDSMDR

Sequence Three Letter Code: 5-FAM-Glu-Asp-Ile-Ile-Arg-Asn-Ile-Ala-Arg-His-Leu-Ala-Gln-Val-Gly-Asp-Ser-Met-Asp-Arg-OH

Chemical Formula:C116H171N33O38S1

Molecular Weight: 2668

Purity: 95%

Form: Lyophilized

Storage Conditions: - 20 °C Protected from light

Research Area: Cancer Disease Research

Source / Species: human

Conjugation: Conjugated

Conjugation Type: Fluorescent dyes

Code Nacres: NA.26

Application: The 5-FAM–labeled Bid BH3 peptide (residues 80–99) represents the BH3 domain of the pro-apoptotic protein Bid, a BH3-only member of the BCL-2 family that plays a key role in linking extrinsic death receptor signaling to mitochondrial activation of the intrinsic apoptotic pathway. This domain mediates critical interactions with anti-apoptotic BCL-2 family proteins, promoting mitochondrial outer membrane permeabilization and downstream apoptotic signaling. By incorporating a 5-carboxyfluorescein (5-FAM) fluorescent label, this peptide enables sensitive detection in fluorescence-based assays and is widely used for studying BCL-2 family protein–protein interactions, apoptosis signaling pathways, and mitochondrial priming. The fluorescent Bid BH3 peptide is particularly suitable for fluorescence polarization assays, competitive binding assays, and inhibitor screening, allowing researchers to evaluate compounds that modulate BH3-dependent interactions. It serves as a valuable research tool for investigating apoptosis regulation, cancer biology, and therapeutic strategies targeting the BCL-2 protein family.

Current Research: Programmed cell death, or apoptosis, is a fundamental biological process that maintains tissue homeostasis and eliminates damaged or potentially harmful cells. The mitochondrial apoptotic pathway is tightly controlled by the BCL-2 family of proteins, which includes both pro-apoptotic and anti-apoptotic members that regulate mitochondrial outer membrane permeabilization (MOMP). Among these regulators, BH3-only proteins act as key initiators of apoptosis by engaging anti-apoptotic BCL-2 family proteins and activating pro-apoptotic effectors. The Bid BH3 peptide (residues 80–99) represents the BH3 domain of Bid (BH3-interacting domain death agonist), a pro-apoptotic BCL-2 family member that links extrinsic death receptor signaling to mitochondrial apoptotic activation. When labeled with the fluorescent dye 5-carboxyfluorescein (5-FAM), the peptide becomes a powerful tool for investigating BH3-dependent protein interactions and apoptosis signaling pathways in fluorescence-based assays. Bid and the BH3 Domain in Apoptosis Bid belongs to the BH3-only subgroup of the BCL-2 protein family. These proteins serve as sentinels of cellular stress, transmitting apoptotic signals to mitochondria. In particular, Bid plays a crucial role in connecting extrinsic apoptosis pathways, initiated by death receptors such as Fas and TRAIL receptors, to the intrinsic mitochondrial pathway. Following activation of death receptor signaling, Bid is cleaved by caspase-8 to produce truncated Bid (tBid). This active form translocates to mitochondria, where it interacts with other BCL-2 family proteins to promote mitochondrial membrane permeabilization. The BH3 domain of Bid is the essential structural motif responsible for these interactions. This short α-helical sequence binds to hydrophobic grooves present in anti-apoptotic proteins such as: BCL-2 BCL-XL MCL-1 BCL-W Through these interactions, BH3-only proteins neutralize anti-apoptotic factors and allow activation of the pro-apoptotic effectors BAX and BAK, which form pores in the mitochondrial outer membrane. This event triggers the release of cytochrome c and other apoptogenic factors that activate downstream caspases and drive the apoptotic program. Design of the 5-FAM–Labeled Bid BH3 Peptide The Bid BH3 peptide (80–99) reproduces the key sequence within Bid responsible for binding BCL-2 family proteins. This synthetic peptide allows researchers to isolate and study BH3-dependent interactions in controlled biochemical experiments. To facilitate detection and quantitative measurement, the peptide is labeled with 5-carboxyfluorescein (5-FAM), a widely used fluorescent dye. 5-FAM exhibits strong fluorescence with excitation and emission maxima typically around 495 nm and 520 nm, making it compatible with many fluorescence detection systems. The fluorescent label enables sensitive monitoring of peptide binding events and molecular interactions in solution or high-throughput screening assays. Studying BCL-2 Family Protein Interactions The Bid BH3 peptide serves as a model ligand for analyzing interactions between BH3 domains and anti-apoptotic BCL-2 proteins. Because these interactions are central to the regulation of mitochondrial apoptosis, understanding their molecular details is important for both basic biology and therapeutic research. Using the fluorescent peptide, researchers can measure how strongly different BCL-2 proteins bind to BH3 motifs and how mutations or structural variations influence these interactions. Such studies help clarify the mechanisms controlling mitochondrial priming, a state in which cells become more sensitive to apoptotic signals. Applications in Fluorescence-Based Assays The 5-FAM–labeled Bid BH3 peptide is particularly useful in fluorescence-based binding assays that quantify protein–peptide interactions. Common experimental formats include: Fluorescence polarization (FP) assays In FP assays, binding of the fluorescent BH3 peptide to larger proteins reduces its rotational mobility, resulting in measurable changes in fluorescence polarization. Competitive binding assays Researchers can introduce candidate molecules that compete with the BH3 peptide for binding to BCL-2 family proteins. Decreased fluorescence signal indicates displacement of the labeled peptide. High-throughput inhibitor screening These assays are frequently used to identify compounds that disrupt BCL-2 family interactions, a strategy that has proven valuable in drug discovery. Because of its robust fluorescence signal and well-defined binding properties, the Bid BH3 peptide is particularly well suited for these quantitative approaches. Relevance to Cancer Biology and Therapeutic Development Dysregulation of apoptosis is a hallmark of cancer. Many tumor cells overexpress anti-apoptotic BCL-2 proteins, which allow them to evade programmed cell death and survive under conditions that would normally trigger apoptosis. Therapeutic strategies targeting BCL-2 family interactions have therefore become an important area of oncology research. BH3 mimetics, small molecules that mimic BH3 domain activity, are designed to disrupt anti-apoptotic protein function and restore apoptotic sensitivity in cancer cells. Fluorescent BH3 peptides, including the 5-FAM–labeled Bid BH3 sequence, play an important role in screening and characterizing these compounds. Advancing Research on Apoptotic Regulation The 5-FAM–labeled Bid BH3 peptide (80–99) provides a convenient and sensitive probe for studying the molecular interactions that regulate mitochondrial apoptosis. By enabling quantitative analysis of BH3-dependent binding events, the peptide supports research on BCL-2 family protein interactions, mitochondrial priming, and apoptosis signaling pathways. Through its application in fluorescence polarization assays, competitive binding studies, and inhibitor screening, this fluorescent peptide continues to facilitate advances in apoptosis research, cancer biology, and the development of therapies targeting BCL-2 family proteins.