MHV NSP3 contains a DPUP that is located N-terminal to the ubiquitin-like domain 2 (Ubl2) and papain-like protease 2 (PLP2) catalytic domain. It is structurally similar to the Severe Acute Respiratory Syndrome (SARS) CoV unique domain C (SUD-C), adopting a frataxin-like fold that has structural similarity to DNA-binding domains of DNA-modifying enzymes. SUD-C is also located N-terminal to Ubl2 and PLP2 in SARS NSP3, similar to the DPUP of MHV NSP3; however, unlike DPUP, it is preceded by SUD-N and SUD-M macrodomains that are absent in MHV NSP3. Though structurally similar, there is little sequence similarity between DPUP and SUD-C. SARS SUD-C has been shown to bind to single-stranded RNA and recognize purine bases more strongly than pyrimidine bases; it also regulates the RNA binding behavior of the SARS SUD-M macrodomain. It is not known whether DPUP functions in the same way [].This entry represents the DPUP (domain preceding Ubl2 and PLP2) of murine hepatitis virus (MHV) non-structural protein 3 (NSP3) and other NSP3s from betacoronaviruses in the embecovirus subgenera (A lineage), including human CoV OC43, rabbit CoV HKU14 and porcine hemagglutinating encephalomyelitis virus (HEV), among others.
