J. biol. chem. J. biol. chem. Substrate specificity of the pyrophosphohydrolase LpxH determines the asymmetry of Bordetella pertussis lipid A Arenas Jesús Universidad de Zaragoza Pupo Elder de Jonge Eline Pérez-Ortega Jesús Schaarschmidt Joerg van der Ley Peter Tommassen Jan 2019 research-article