HR2

HR2 is an acronym used in several different fields, and there is no single universally accepted definition. In biology and virology, HR2 most commonly refers to the second heptad repeat region in class I viral fusion proteins. In these proteins, HR2 works with the HR1 region to form a six-helix bundle that drives the fusion of viral and host cell membranes. Because of its role in fusion, HR2-derived peptides have been investigated as antiviral inhibitors, and the HR1–HR2 interaction is a target in drug design for viruses such as HIV-1 and coronaviruses.

In the United Kingdom, HR2 is a postcode district within the Hereford postcode area. The district is used for mail routing and geographic reference, and, like other districts labeled with HRx, it helps identify a portion of the Hereford region.

Other uses of HR2 exist in specialized or commercial contexts, where HR2 may serve as a model number, version code, or designation within a product line. These uses are typically company-specific and not widely standardized.