• Erythrocyte;
  • Linker histones;
  • Liquid chromatography–linear quadrupole ion trap–Fourier transform mass spectrometry;
  • Muscovy duck;
  • Polyacrylamide gel electrophoresis;
  • Putrescine


Linker Histone-Like proteins (LHL1 and LHL2) were identified within a linker histone complement of Muscovy duck erythrocyte chromatin. Polyacrylamide gel electrophoretic patterns of N-bromosuccinimide-cleaved LHL products as well as liquid chromatography-electrospray-ion trap mass spectrometry analyses of trypsin-digested LHL peptides revealed structural similarity of LHL1 to histone H5 and between LHL2 and histone H1 subtypes.

Since the LHL proteins were stable in the presence of 2-mercaptoethanol and dithiothreitol that reduce disulfide bonds, it appeared unlikely that this doublet was a thiol-derived product of linker histones. A loss of LHL1, with a concomitant maintenance of LHL2 after treatment with dilute alkali, seems to suggest that they might represent disparate protein conjugates resulting from linker histone modifications through ester linkages.