The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)
 
 
 
 
 

Characterization of thyroid hormone binding to apolipoprotein-E: localization of the binding site in the exon 3-coded domain.

Apolipoprotein-E (apoE) has been shown by noncovalent binding and photoaffinity labeling with [125I]T4 to possess a single L-T4 binding site with a K5 of about 3 x 10(7) M-1 and a relative affinity for analogs of L-T4 = D-T4 = rT3 = triiodothyroacetic acid > L-T3. T4 binding was not affected by the flavonoid EMD 21388 or heparin, but was inhibited by diclofenac = mefenamic acid > furosemide. Localization of the T4 site to the N-terminal 62-amino acid region of the mature peptide coded by exon 3 was deduced from the following evidence. 1) The N-terminal 15- to 26-kilodalton (kDa) fragments (within residues 1-160 to 210), but not the approximately 10- to 11-kDa fragments (within residues approximately 220-299), were labeled by [125I]T4. 2) Variants apoE2 and apoE4, with nonconservative mutations at positions 112 and 158 (the latter unable to interact with the apoB/E receptor), maintained the ability to bind T4. 3) Monoclonal antibodies MAb 1D7 and 3H1 (epitopes at positions 139-169 and 243-272, respectively) failed to inhibit T4 binding, but MAb 6H7 (epitope at 1-125) decreased labeling by about 24%. 4) Polymers of apoE were specifically labeled despite the interaction between amphipathic alpha-helices of the exon 4-encoded region (63-299). We conclude that apoE, as previously observed with apoA-I and apoB, possesses a T4-binding domain separate from the lipid-binding domain and distinct from both the heparin- and the cell receptor-binding sites. Thyroid hormone binding by apoE may facilitate uptake of the hormone by cells through apoB/E receptors, which are widely distributed in tissues.[1]

References

 
WikiGenes - Universities