Precursor terminal protein (Adenovirus 5) (pTP)

The Adenovirus 5 precursor terminal protein (pTP) is an essential 87 kDa viral protein encoded by the E2B region of the human adenovirus type 5 genome (UniProt P04499). It plays a fundamental role in the initiation of viral DNA replication by serving as a protein primer, a mechanism distinct from the RNA-priming used by host cells (NIH, 2.1.1). During initiation, pTP forms a stable complex with the viral DNA polymerase (AdPol), and the polymerase catalyzes the covalent attachment of the first nucleotide (dCMP) to a specific serine residue (Ser-580) within pTP (PNAS, 2.2.3). This pTP-dCMP complex then provides the 3-OH group necessary for the elongation of the nascent DNA strand (ResearchGate, 3.3.4). Beyond replication, pTP is involved in anchoring the viral genome to the nuclear matrix and protecting the ends of the linear double-stranded DNA from degradation (NIH, 2.3.2). During the late stages of infection, pTP is proteolytically processed by the adenovirus protease (AVP) into the mature 55 kDa terminal protein (TP), which remains covalently attached to the 5' ends of the viral DNA in the mature virion (UniProt, 3.2.1). Given its indispensable role in the viral life cycle and its unique priming mechanism, pTP is a high-priority target for the development of specific anti-adenoviral agents, particularly for treating severe infections in immunocompromised patients where current off-label therapies like cidofovir have limited efficacy and significant toxicity (MDPI, 3.1.3).

Other names

Preterminal protein87K proteinTerminal protein precursorE2B proteinpTP

Inhibition of viral DNA replication by interfering with the pTP-DNA polymerase complex or chain termination of the nascent DNA strand.