Binds double-stranded DNA tightly but without sequence specificity. It is distributed uniformly and abundantly on the chromosome, suggesting a role in chromatin architecture. May be involved in DNA compaction. Binds rRNA and mRNA in vivo. May play a role in maintaining the structural and functional stability of RNA, and, perhaps, ribosomes. Highly active above 45 degrees Celsius. Poorly active at 25 degrees Celsius. Homodimer. Two forms exist in solution due to isomerization of the Leu-61/Pro-62 peptide bond. The trans (T) form of the dimer dominates at higher temperatures, whereas the population of the cis (C) form increases at lower temperatures. The T form causes DNA to adopt a supercoiled conformation. Acetylated. Deacetylation by the SIR2-homolog deacetylase may regulate its activity (By similarity). Belongs to the histone-like Alba family.