TABLE 2.

Interhelical hydrogen bonds in the apoE N-terminal domain NMR structure

Residues highlighted in bold are completely buried residues, and residues in plain text are partially buried residues. Buried H-bonds that are between helices N/C and the bundle are underlined. “s” stands for side chain atom, and “b” stands for the backbone atom that forms the H-bonds.

	Helix N	Helix 1	Helix 1′	Helix 2	Loop 2	Helix 3	Helix 4
Helix 2		Trp-26b—Glu-70s	Glu-50s—Gln-55sa
		Arg-25b—Glu-70s	Glu-50b—Val-56ba
Helix 3	Lys-1b—Arg-92sb
Helix 4	Gln-21s—Gln-163b	Leu-37b—Arg-145s	Glu-45s—Arg-134sb	Tyr-74s—Leu-159bc	T83s-V161ba	Asp-107s—Leu-144b
	Ser-22s—Gln-163s	Glu-27s—Gln-156s				Asp-107s—Arg-147s
						Asp-107s—Leu-148b
Helix C				Glu-79s—Pro-183b		Ser-94s—Glu-179s

^aThe buried H-bonds between helices 1′ and 2 and between loop 2 and helix 4 favor helix bundle recovery via the preferred helix bundle opening.

^bThese are exposed H-bonds.

^cThis buried H-bond favors helix bundle recovery via both preferred and non-preferred bundle openings.