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Figure 3.
Fig. 3. SOLOMON map covering 80s loop. The initial map after density modification and phase extension with SOLOMON ~Abra-
hams & Leslie, 1996! shows the 80s loop is clearly traceable in model-free maps. The H2--H3 connecting loop, or 80s loop, has not
been previously observed in any of the numerous structure determinations of apoE and variants. The quality of this map demonstrates
clearly the advantage of current crystallographic techniques for revealing new details. The 80s loop adopts a pseudo-b conformation
that is stabilized by side-chain--main-chain hydrogen bonds ~not shown!. The 80s loop is rich in acidic residues and is probably involved
in initial lipid binding through charge complementarity with positively charged phosphatidylcholine head groups.
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