This outer membrane lipoprotein carries a TPR-like region towards its N-terminal. YfiO in E.coli is one of three outer membrane lipoproteins that form a multicomponent YaeT complex in the outer membrane of Gram-negative bacteria that is involved in the targeting and folding of beta-barrel outer membrane proteins. YfiO is the only essential lipoprotein component of the complex. It is required for the proper assembly and/or targeting of outer membrane proteins to the outer membrane. Through its interactions with NlpB it maintains the functional integrity of the YaeT complex.

1: YfiO stabilizes the YaeT complex and is essential for outer membrane protein assembly in Escherichia coli. Malinverni JC, Werner J, Kim S, Sklar JG, Kahne D, Misra R, Silhavy TJ; Mol Microbiol. 2006;61:151-164. PMID:16824102