Heparin binding by the HIV-1 tat protein transduction domain.
The protein transduction domain from the HIV-1 tat protein (termed PTD-tat) has been fused to the C-terminus of a model cargo protein, the IgG binding domain of streptococcal protein G. We demonstrate that PG-Ctat (PTD-tat fused to the C-terminus of protein G) binds to a heparin affinity column. PG-Ctat binds with relatively high affinity, as shown by its elution at 1.6 M NaCl. The heparin binding properties of PTD-tat are consistent with the idea that heparan sulfate, an analog of heparin found at the cell surface, plays a role in the translocation of PTD-tat fusions. We suggest that the heparin-binding properties of PTD-tat can be exploited for purification of PTD-tat fusions in the absence of affinity tags.
Hakansson
S
S
Department of Biochemistry and Molecular Biology, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
Jacobs
A
A
Caffrey
M
M
D015696:Gene Products, tat / Q000378:metabolism*; D015497:HIV-1 / Q000737:chemistry*; D006493:Heparin / Q000378:metabolism*; D006497:Heparan Sulfate / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000502:physiology; D021381:Protein Transport; D013291:Streptococcus / Q000737:chemistry; D054322:tat Gene Products, Human Immunodeficiency Virus
D015696:Gene Products, tat; D006493:Heparin; D006497:Heparan Sulfate; D009419:Nerve Tissue Proteins; D054322:tat Gene Products, Human Immunodeficiency Virus; C029152:G-substrate