Before revision:  In binary  DPPC:CHOL  mixtures, both cholesterol and DPPC acyl chains were observed spontaneously entering deep "non-annular" cavities in the nAChR TMD, particularly at the subunit interface and the \beta subunit center, facilitated by the low amino acid density in the cryo-EM structure of nAChR in a native membrane.
After revision:  In binary Dipalmitoylphosphatidylcholine:Cholesterol ( DPPC:CHOL mixtures, both cholesterol and DPPC acyl chains were observed spontaneously entering deep "non-annular" cavities in the nAChR TMD, particularly at the subunit interface and the \beta subunit center, facilitated by the low amino acid density in the cryo-EM structure of nAChR in a native membrane.