SUMMARYHistone H1 inLeishmaniapresents relevant differences compared to higher eukaryote counterparts, such as the lack of a DNA-binding central globular domain. Despite that, it is apparently fully functional since its differential expression levels have been related to changes in chromatin condensation and infectivity, among other features. The localization and the aggregation state ofL. braziliensisH1 has been determined by immunolocalization, mass spectrometry, cross-linking and electrophoretic mobility shift assays. Analysis of H1 sequences from theLeishmaniaGenome Database revealed that our protein is included in a very divergent group of histones H1 that is present only inL. braziliensis.An antibody raised against recombinantL. braziliensisH1 recognized specifically that protein by immunoblot inL. braziliensisextracts, but not in otherLeishmaniaspecies, a consequence of the sequence divergences observed amongLeishmaniaspecies. Mass spectrometry analysis andin vitroDNA-binding experiments have also proven thatL. braziliensisH1 is monomeric in solution, but oligomerizes upon binding to DNA. Finally, despite the lack of a globular domain,L. braziliensisH1 is able to form complexes with DNAin vitro, with higher affinity for supercoiled compared to linear DNA.
Analysis of Glycerophospholipid Hydroperoxides by Ion Spray Mass Spectrometry
