<p>This entry represents a structural domain with an alpha-helical, orthogonal bundle fold. Domains with this structure are found at the N-terminal (zinc-binding domain) of HIV integrase, and in the following hypothetical proteins: YebC from <taxon tax_id="562">Escherichia coli</taxon>, HP0162 from <taxon tax_id="210">Helicobacter pylori</taxon> (Campylobacter pylori) and aq1575 from <taxon tax_id="63363">Aquifex aeolicus</taxon> [<cite idref="PUB00027019"/>].</p><p>Retroviral integrase mediates integration of a DNA copy of the viral genome into the host chromosome. Integrase is composed of three domains: an N-terminal zinc binding domain, a central catalytic core and a C-terminal DNA-binding domain [<cite idref="PUB00026646"/>, <cite idref="PUB00024383"/>]. It is often found as part of the POL polyprotein.</p>