Contribution of the carboxy-terminal domain of lipoprotein lipase to interaction with heparin and lipoproteins.
The C-terminal domain of lipoprotein lipase (LPL) is involved in several important interactions. To assess its contribution to the binding ability of full-length LPL we have determined kinetic constants using biosensor technique. The affinity of the C-terminal domain for heparin was about 500-fold lower than that of full-length LPL (K(d) = 1.3 microM compared to 3.1 nM). Replacement of Lys403, Arg405 and Lys407 by Ala abolished the heparin affinity, whereas replacement of Arg420 and Lys422 had little effect. The C-terminal domain increased binding of chylomicrons and VLDL to immobilized heparin relatively well, but was less than 10% efficient in binding of LDL compared to full-length LPL. Deletion of residues 390-393 (WSDW) did not change the affinity to heparin and only slightly decreased the affinity to lipoproteins. We conclude that the C-terminal folding domain contributes only moderately to the heparin affinity of full-length LPL, whereas the domain appears important for tethering triglyceride-rich lipoproteins to heparin-bound LPL.
Lookene
A
A
National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn, 12618, Estonia.
Nielsen
M S
MS
Gliemann
J
J
Olivecrona
G
G
D000818:Animals; D002417:Cattle; D004305:Dose-Response Relationship, Drug; D006493:Heparin / Q000378:metabolism*; D006497:Heparan Sulfate / Q000378:metabolism; D007477:Ions; D007700:Kinetics; D008071:Lipoprotein Lipase / Q000737:chemistry* / Q000378:metabolism*; D008074:Lipoproteins / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012965:Sodium Chloride / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D020349:Surface Plasmon Resonance; D013997:Time Factors
D006493:Heparin; D006497:Heparan Sulfate; D007477:Ions; D008071:Lipoprotein Lipase; D008074:Lipoproteins; D011994:Recombinant Proteins; D012965:Sodium Chloride