Replication protein E1

Function

Replication protein E1 (RPE1) is a human papillomavirus (HPV) essential protein which is required for its replication. RPE1 recognizes the HPV origin of replication (ori) with the aid of regulatory protein E2 (RPE2). The resultant helicase complex initiates DNA unwinding to provide the template of progeny DNA synthesis, The HPV ori contains one RPE1 binding site and 2 RPE2 binding sites^[1]. RPE1 is found also in bovine papillomavirus (BPV).

Disease

RPE1 has been shown to mitigate host cell defenses leading to the development of cancer induces apoptosis of its host cells^[2].

Relevance

The detection of RPE1 mRNA and promoter methylation may serve as cancer prognostic marker.

Structural highlights

The complex between BPV1 DBD and 21-bp DNA (PDB code 1ksx) shows 2 DBD-DNA binding modules: a binding loop and a binding helix each interacting with a single strand. The protein-DNA interactions are hydrophilic to phosphate atoms and van der Waals hydrophobic ones^[3].