8aqd is a 1 chain structure with sequence from Streptomyces avidinii. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
[SAV_STRAV] The biological function of streptavidin is not known. Forms a strong non-covalent specific complex with biotin (one molecule of biotin per subunit of streptavidin).