Table 1.

X-ray Reflectivity Box Fit Parameters. Errors reported are standard deviations obtained from the non-linear least square fitting of the reflectivity data with box models using the Levenberg-Marquadt algorithm (53).

Sample	Box Composition	Thickness (Å)	ρ/ρH2O	Roughness (Å)
hTau40	Air/protein interface	7.99 ± 2.4E-2	1.27 ± 4.8E-3	2.66 ± 1.5E-3
	Protein/subphase interface	7.93 ± 5.6E-2	1.02 ± 3.9E-3	2.37 ± 4.7E-4
DMPG	Lipid tails	14.9 ± 4.3E-2	0.94 ± 1.1E-2	3.11 ± 1.3E-3
	Lipid heads	9.78 ± 8.1E-2	1.37 ± 1.4E-2	2.91 ± 3.7E-3
DMPG + hTau40 t1	Lipid tails	13.4 ± 5.2E-1	0.93 ± 1.4E-1	2.96 ± 5.3E-2
	Lipid tails + heads + hTau40	10.3 ± 1.2E-1	1.32 ± 1.6E-2	3.19 ± 4.9E-1
	hTau40	10.1 ± 1.2E0	1.01 ± 2.9E-2	3.33 ± 6.1E-1
DMPG + hTau40 t2	Lipid tails	12.3 ± 6.5E-2	0.91 ± 1.7E-2	3.25 ± 3.1E-1
	Lipid tails + heads + hTau40	11.2 ± 1.8E-1	1.25 ± 2.1E-2	3.25 ± 1.1E0
	hTau40	9.01 ± 3.7E-1	1.04 ± 2.7E-2	2.33 ± 7.8E-1