8.A.99. The BLP Braun's Lipoprotein (Lpp) Family Gram-negative bacteria such as Escherichia coli are protected by a complex cell envelope with covalent and noncovalent protein interactions linking the outer membrane to the aqueous periplasmic region. Samsudin et al. 2017 showed that Braun's lipoprotein tilts and bends, and thereby lifts the cell wall closer to the outer membrane. Both monomers and dimers of the outer membrane porin OmpA can interact with peptidoglycan in the presence of Braun's lipoprotein, but in the absence of the latter, only dimers of OmpA show a propensity to form contacts with peptidoglycan. This provides one mechanism by which the cell wall attaches to the outer membrane (Samsudin et al. 2017).
References:
Samsudin, F., A. Boags, T.J. Piggot, and S. Khalid. (2017). Braun's Lipoprotein Facilitates OmpA Interaction with the Escherichia coli Cell Wall. Biophys. J. 113: 1496-1504.
Examples:
TC#	Name	Organismal Type	Example
8.A.99.1.1	Braun's lipoportein, BLP, Lpp, MlpA, MulI, of 78 aas with an N-terminal TMS. It functions to bind OmpA (TC# 1.B.6.1.1) to connect the outer membrane to the peptidoglycan cell wall (Samsudin et al. 2017).		BLP of E. coli

8.A.99.1.2	Putative lipoportein of 86 aas and 1 N-terminal TMS.		LP of Colwellia polaris

8.A.99.1.3	Putative lipoprotein of 89 aas and 1 N-terminal TMS.		LP of Stenotrophomonas panacihumi

8.A.99.1.4	Uncharacterized lipoprotein of 92 aas and 1 N-terminal TMS.		UP of Methylocaldum szegediense