Synaptic Systems - ALFA sdAb

ALFA sdAb - N1505-DBCO

A rationally designed epitope tag

This product was developed by

Camelid single domain antibodies consist only of one antigen binding site of a Alpaca heavy chain antibody. With only ~15 kDa, these Tags are about 10-times smaller than conventional IgG antibody molecules. FluoTags carry fluorophore molecules coupled in a site specific manner.

The ALFA-tag is a novel, rationally designed epitope tag (SRLEEELRRRLTE) that forms a small and stable α-helix that is functional irrespective of its position on the target protein in prokaryotic and eukaryotic hosts.

Camelid single domain antibody

Background

The ALFA-tag is a novel, rationally designed epitope tag (SRLEEELRRRLTE) that forms a small and stable α-helix that is functional irrespective of its position on the target protein in prokaryotic and eukaryotic hosts.
The ALFA-tag has the broadest spectrum of applications in life sciences compared to any other tag. NanoTag developed a nanobody binding the ALFA-tag with ~26 pM affinity, which is ideally suited not only for super-resolution microscopy, immunoprecipitations and Western blotting, but also allows detection of proteins within living cells. This nanobody can be conjugated to virtually all kinds of fluorophores, enyzmes or other biomolecules.
Unlabeled variants and several modifications of sdAbs like biotin, fluorophore or DBCO conjugation are available.

In FluoTag®-X2 two fluorophore molecules are site-specifically coupled to each FluoTag molecule. Therefore, the reagent simultaneously targets two fluorophores to the protein of interest, which ensures up to two-fold („2X“)-brighter signals. Owing to the small size of the FluoTags, the distance between the target epitope and each fluorophore is ~ 3 nm.
In comparison to detection systems using conventional antibodies, FluoTag-X can thus improve the localization accuracy by 10-15 nm. Both features - superior brightness and precise fluorophore placement - render the FluoTag-X products excellent tools for all microscopy techniques.

Cat. No. N1505-DBCO	250 µg purified antibody, lyophilized from PBS, fluorescence-labeled with DBCO. Dibenzocyclooctyne (DBCO, ADIBO) is one of the most reactive cycloalkynes for strain promoted alkyne azide cycloaddition (spAAC), a copper-free click chemistry reaction. Albumin was added for stabilization. For reconstitution add 250 µl H₂O to get a 1mg/ml solution in PBS. Either add 1:1 (v/v) glycerol, then aliquot and store at -20°C until use, or store aliquots at -80°C without additives. Reconstitute immediately upon receipt! Avoid bright light when working with the antibody to minimize photo bleeching of the fluorescent dye.
Applications	WB: yes ICC: yes IHC: yes FACS: yes Western blot (WB); separation of proteins by PAGE and subsequent transfer to a membrane. Detection of target molecules is carried out with antibodies. Some antibodies require special sample preparation steps. For details, please refer to the “Remarks” section. Immunocytochemistry (ICC) on 4% PFA fixed cells. Immunoreactivity is usually revealed by fluorescence. Some antibodies require special fixation methods. For details, please refer to the “Remarks” section. Immunohistochemistry (IHC) on 4% PFA perfusion fixed tissue with 24h PFA post fixation. Immunoreactivity is usually revealed by fluorescence or a chromogenic substrate. Some antibodies require special fixation methods or antigen retrieval steps. For details, please refer to the ”Remarks” section. Fluorescence-activated cell sorting (FACS); usually cells are fluorescently labeled with antibodies against cell-surface antigens followed by cell-sorter analysis.
Label	DBCO
Clone	1G5
Immunogen	Synthetic peptide corresponding to: SRLEEELRRRLTE (UniProt Id: not defined)
Specificity	ALFA-tag