Members of the DNABII family of DNA-binding proteins, IHF (integration host factor) and HU (histone-like protein), are known for their strong structural influences on DNA intracellularly, and are also critical to the stability of the lattice-like 3D DNA structure found in biofilm matrices extracellularly. Extracellular DNA and DNABII protein are essential structural components of the extracellular polymeric substance, or matrix, of the nontypeable Haemophilus influenzae biofilm.