... presence of a two-fold axis, all of the inter-actions reported below are repeated twice; that is, if Ala25 ofchain A is close to Asn77 of chain B, then Asn77 of chain A isclose to Ala25 of chain B.Chain ... diffracts to a Table 1. Statistics on data collection and refinement. A wavelength of 0.8726 A ˚was used. Rotations of 1° were performed. The Ramachan-dran plot was calculated usingRAMPAGE.X-ray ... chain B.Chain A Chain B Hydrogen bondsAla25 Asn77, Arg80 AlaO–ArgNH1AlaO–ArgND2Asn26 His35, Arg80, Asn39 AsnOD1–ArgNH1AsnOD1–HisNE2Ser28 Arg76Trp30 Arg42, Trp30, Arg76His35 Glu178, Asn26 HisNE2–AsnOD1Phe36...