Table 1. Observed ²H Quadrupolar Splitting Magnitudes (kilohertz) for Labeled Alanines in Aligned Samples of GWALP23 and Arg-Containing Derivatives in DOPC Bilayers^a.

				|Δνq| (kHz) for the indicated labeled Ala residue in sequence
peptide	label typeb	pH	cholesterol contentc	A7	A9	A11	A13	A15	A17
GWALP23	CD3	–	0 or 20%	16.6	1.7	16.7	1.5	15.4	2.6
GWALP23-R14	CD3	2–13	0 or 20%	26.5	5.5	16	13.1	1.3	28.1
GWALP23-R12	CD3	5.5	20%	27	56	–	–	21.5	29.3
GWALP23-R12	CαD	5.5	20%	95	111	–	–	–	–

^aOriented bilayer samples were prepared on glass plates with 10 mM buffer between pH 2 and 13 (see Methods). The data for GWALP23 (unbuffered) in DOPC are from ref (2).

^bSide-chain CD₃ or backbone CαD label on the indicated Ala residue, A7–A17.

^cAmount of cholesterol (mole percent of total lipid) in the DOPC bilayer. The results for GWALP23 and GWALP23-R14 do not depend upon the cholesterol content. GWALP23-R12 occupies multiple states in the absence of cholesterol.¹³