Synonyms
Human SDF-1γ/CXCL12γ
Description
Human CXCL12 is expressed as five isoforms that differ only in the C-terminal tail. The gamma isoform of CXCL12, also known as SDF-1 gamma, is a 12 kDa, heparin-binding member of the CXC (or alpha) family of chemokines ,Mature SDF-1 molecules are not glycosylated and exhibit a typical three antiparallel beta -strand chemokine-like fold. N-terminal aa 1 8 form a receptor binding site, while aa 1 and 2 (LysPro) are involved in receptor activation. All SDF-1 isoforms can undergo proteolytic processing of the first two N-terminal amino acids by CD26, which is thought to create a reducedactivity chemokine. Human SDF-1 gamma is synthesized as a 119 amino acid (aa) precursor that contains a 21 aa signal sequence and a 98 aa mature region. Mature human SDF-1 gamma shares 99%, 97% and 98% aa identity with mouse, rat, and equine SDF-1 gamma, respectively. The unique Cterminal 26 aa of SDF-1 gamma are highly charged, including four BBXB (where B = basic and X = any aa) motifs, while the most prevalent form, SDF-1 alpha, has 4 unique Cterminal aa and binds heparin via the shared BBXB site more Nterminally located . The SDF1 gamma Cterminus binds heparin in secreted SDF-1 gamma, or targets the isoform to the nucleolus in the absence of a signal sequence. SDF-1 isoforms interact with CXCR4 and CXCR7 receptors on the cell surface, and can also bind syndecan-4.
Molecular Weight
Approximately11.6 kDa
AA sequence
GKPVSLSYRC PCRFFESHVA RANVKHLKIL NTPNCALQIV ARLKNNNRQV CIDPKLKWIQ EYLEKALNKG RREEKVGKKE KIGKKKRQKK RKAAQKRKN
Appearance
Sterile Filtered White lyophilized (freeze-dried) powder.
Purity
> 96% by SDS-PAGE and HPLC analyses.
Biological Activity
Fully biologically active when compared to standard. The biological activity determined by a chemotaxis bioassay using PHA and rHuIL-2 activated human peripheral blood T-lymphocytes is in a concentration range of 30-100 ng/mL.
Endotoxin
<0.1 EU/μg of protein as determined by LAL method.
Formulation
Lyophilized from a 0.2 μm filtered concentrated solution in 20 mM PB, pH 7.4, 150 mM NaCl.
Reconstitution
We recommend that this vial be briefly centrifuged prior to opening to bring the contents to the bottom. Reconstitute in sterile distilled water or aqueous buffer containing 0.1 % BSA to a concentration of 0.1-1.0 mg/mL. Stock solutions should be apportioned into working aliquots and stored at ≤ -20 °C. Further dilutions should be made in appropriate buffered solutions.