The HRDC (helicase and RNaseD C-terminal) domain is comprised of two orthogonally packed α-hairpin subdomains, and is involved in interactions with DNA and protein. It has been suggested that this domain plays a role dissolving double Holliday junctions efficiently [ PUBMED:25901030 ].

HRDC domains are found … expand

The HRDC (helicase and RNaseD C-terminal) domain is comprised of two orthogonally packed α-hairpin subdomains, and is involved in interactions with DNA and protein. It has been suggested that this domain plays a role dissolving double Holliday junctions efficiently [ PUBMED:25901030 ].

HRDC domains are found at the C terminus of many RecQ helicases, including the human Bifunctional 3'-5' exonuclease/ATP-dependent helicase WRN and RecQ-like DNA helicase BLM [ PUBMED:25901030 PUBMED:10647186 ]. RecQ helicases have been shown to unwind DNA in an ATP-dependent manner. The structure of the HRDC domain consists of a 4-5 helical bundle of two orthogonally packed α-hairpins, and as such it resembles auxiliary domains in bacterial DNA helicases and other proteins that interact with nucleic acids. A positively charged region on the surface of the HRDC domain is able to interact with DNA.

The HRDC domain is also present in eukaryotic and archaeal RNA polymerase II subunit RBP4, the N-terminal of which forms a heterodimerisation α-hairpin [ PUBMED:15591044 PUBMED:11741548 ].

The HRDC domain has a putative role in nucleic acid binding. Mutations in the HRDC domain associated with the human BLM gene result in Bloom Syndrome (BS), an autosomal recessive disorder characterised by proportionate pre- and postnatal growth deficiency; sun-sensitive, telangiectatic, hypo- and hyperpigmented skin; predisposition to malignancy; and chromosomal instability [ PUBMED:9397680 ].