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H2A.Bbd is an unusual histone variant whose sequence is only 48% conserved compared to major H2A. The major sequence differences are in the docking domain that tethers the H2A–H2B dimer to the (H3–H4)₂ tetramer; in addition, the C‐terminal tail is absent in H2A.Bbd. We assembled nucleosomes in which H2A is replaced by H2A.Bbd (Bbd‐NCP), and found that Bbd‐NCP had a more relaxed structure in which only 118±2 bp of DNA is protected against digestion with micrococcal nuclease. The absence of fluorescence resonance energy transfer between the ends of the DNA in Bbd‐NCP indicates that the distance between the DNA ends is increased significantly. The Bbd docking domain is largely responsible for this behavior, as shown by domain‐swap experiments. Bbd‐containing nucleosomal arrays repress transcription from a natural promoter, and this repression can be alleviated by transcriptional …