NMR Studies of Human Apolipoprotein-E N-terminal Domain
EMSL Project ID
2128
Abstract
This research proposal is centered on NMR structural studies of human apolipoprotein-E (apoE). ApoE plays important roles in several human diseases, including atherosclerosis and Alzheimers diseases. We will particularly focus on solving the full-length apoE N-terminal domain, apoE(1-183). Although there is a X-ray crystal structure available for this domain, this structure only contains residue 23-166, whereas the rest of the regions have not yet been seen in the crystal structure. Recent experimental data indicates that several residues beyond region 23-166 are critical in apoE LDL receptor binding activity. These results indicate that more structural studies of the apoE N-terminal domain are required to resolve these problems. The X-ray crystal structure indicates that residues beyond 23-164, either at the N-terminus or the C-terminus, are flexible and have no observable electron density map in the X-ray diffraction. Thus, NMR structural studies of the apoE N-terminal domain may provides a possible solution to these issues. Further, preliminary experimental evidence suggests that apoE(1-183) provides the complete LDL receptor binding activity for apoE. We have 2H/15N/13C-triple labeled apoE(1-183) for 3D/4D heteronuclear NMR experiments. Our preliminary NMR studies indicated that apoE(1-183) adopted a similar helix-bundle structure at several different pHs, including pH6.4 and 3.2. Our NMR data further indicates the presence of NMR signals for those residues beyond 23-164 region, suggesting the possibility of a complete NMR assignment for intact apoE(1-183). In addition, this result also suggests that we may obtain a NMR structure of an intact apoE N-terminal domain in solution. We anticipate that a NMR structure of the intact apoE N-terminal domain may provide answers to the above important issues pertaining to the apoE LDL receptor binding activity.
Project Details
Project type
Capability Research
Start Date
2001-04-18
End Date
2001-05-01
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Chen B, X Ren, T Neville, WG Jerome, DW Hoyt, DL Sparks, G Ren, and J Wang. 2009. "Apolipoprotein AI tertiary structures determine stability and phospholipid-binding activity of discoidal high-density lipoprotein particles of different sizes." Protein Science 18(5):921-935. doi:10.1002/pro.101
Xu C, A Sivashanmugam, DW Hoyt, and J Wang. 2005. "A Complete Backbone Assignment of the Apolipoprotein E LDL Receptor Binding Domain [Letter to the Editor]." Journal of Biomolecular NMR 32(2):177.