periplasmiclinked

Periplasmiclinked is a coinage used in microbiology and synthetic biology to describe biomolecular designs or natural interactions that are organized through the periplasmic space of Gram-negative bacteria. The term references the periplasm, the compartment between the inner cytoplasmic membrane and the outer membrane, and emphasizes linkage or connectivity achieved within that space. In practice, periplasmiclinked constructs involve tethering or translocating functional units so that activity can occur in or transit through the periplasm, enabling coordination between cytoplasmic and extracellular processes.

Mechanisms commonly associated with periplasmic linking include fusion of signal peptides to direct proteins to the periplasm via Sec or Tat translocation pathways, use of periplasmic anchor motifs that retain proteins near the inner membrane, and engineered linker sequences that span the periplasm with defined length and rigidity. Disulfide bond formation and redox control (via the Dsb system) are relevant considerations for maintaining functional conformation in the oxidizing periplasm.

Applications of periplasmiclinked design include multi-enzyme pathways that pass intermediates through the periplasm, periplasmic sensing modules connected to cytosolic or extracellular outputs, and biocatalysis leveraging periplasmic enzymes for substrate processing while protecting cytoplasmic components.

Limitations include confinement to Gram-negative bacteria, the complexities of periplasmic transport, and potential leakage or mislocalization. The term remains informal and not widely standardized; researchers may use different definitions or contexts for periplasmic linking.

See also: periplasm, Gram-negative bacteria, Sec pathway, Tat pathway, disulfide bond formation.