Recognition and penetration of the HIV-1 Env glycan shield by potent broadly neutralizing antibodies by Julien J, Kong L, Pejchal R, Khayat R, Lee J, Stanfield RS, Walker LM, Doores KJ, Folkowska E, Poignard P, Depetris R, Sanders RW, Koff WC, Moore JP, Ward AB, Burton DR, Wilson IA