There are few examples of seven-carbon sugars in nature, among which are: The production of heptose is conserved across gram-negative bacteria.
In the form of L-glycero-D-mannose-heptose, heptose is a key component in the secondary membrane of gram-negative bacteria.
[5] These lipopolysaccharides comprise an endotoxin that acts as an immune system agonist and elicits strong responses.
[5] The 7-carbon heptose molecules are essential for stability in the lipopolysaccharide membrane, forming an interconnected network utilizing divalent cations.
[5][6] Along with producing the first synthetic version of HBP, it was shown that the beta form of the heptose acts as a pathogen-associated molecular pattern (PAMP) and activates the NF-kB signaling pathway.