Porin B (PorB) (PorB)

Porin B (PorB) is the primary outer membrane porin of Neisseria species, most notably Neisseria gonorrhoeae and Neisseria meningitidis, where it forms a 16-stranded beta-barrel structure [1, 2]. It is essential for bacterial survival, acting as a selective channel that allows the passage of ions and small hydrophilic nutrients while also serving as the primary entry point for several classes of antibiotics, such as beta-lactams and fluoroquinolones [2, 4]. PorB is highly immunogenic and is a major target for the host's immune system; consequently, it is a focal point for vaccine development efforts aimed at preventing gonococcal and meningococcal infections [5]. Beyond its transport function, PorB acts as a virulence factor by translocating from the bacterial membrane into the host cell's mitochondrial membrane, where it can manipulate apoptotic pathways to favor bacterial persistence [3]. However, the protein exhibits significant antigenic variation, particularly in its surface-exposed loops, which allows the bacteria to evade host immunity and complicates the creation of a universal vaccine [1, 6]. Mutations within the PorB channel can also lead to decreased permeability, contributing to the development of multidrug-resistant bacterial strains [4].

Other names

Major outer membrane proteinProtein IPorB1aPorB1bMOMP

Facilitates the passive diffusion of hydrophilic solutes and antibiotics across the bacterial outer membrane and serves as an antigenic target for bactericidal antibodies [2, 5].