Crystal structure of monomeric Amuc-1100 from Akkermansia muciniphila

Abstract

Many human diseases, such as obesity and diabetes, show annual increases in prevalence and often involve intestinal microbes. One such probiotic bacterium, Akkermansia muciniphila, which was discovered a decade ago, has been reported to influence glucose homeostasis and to contribute to gut health. Amuc-1100, a functionally uncharacterized protein of A. muciniphila, was found to be a key active component in reducing the body weight of mice. Here, the crystal structure of Amuc-1100 (residues 31'317), referred to as Amuc-1100∗, is reported at 2.1 A 'resolution. Amuc-1100∗has a similar fold to three proteins related to pilus formation, PilO, PilN and EpsL, indicating a similar function. Biochemical investigations further confirmed a monomeric state for the soluble region of Amuc-1100, which differs from the dimeric states of PilO, PilN and EpsL. This study provides a structural basis for the elucidation of the molecular mechanism of Amuc-1100.