title: Sequence of horse (Equus caballus) apoA-II. Another example of a dimer forming apolipoprotein.
abstract: Apolipoprotein A-II, the second major apolipoprotein of human HDL, also has been observed in a variety of mammals; however, it is either present in trace amounts or absent in other mammals. In humans and chimpanzee, and probably in other great apes, apoA-II with a cysteine at residue 6 is able to form a homodimer. In other primates as well as other mammals, apoA-II, lacking a cysteine residue, is monomeric. However, horse HDL has been reported to contain dimeric apoA-II that following reduction forms monomers. In this report, we extend these observations by reporting on the first complete sequence for a horse apolipoprotein and by demonstrating that horse apoA-II also contains a cysteine residue at position 6. Both the intact protein and its enzymatic fragments were analyzed by chemical sequence analysis and time-of-flight MALDI-MS (matrix assisted laser desorption ionization mass spectrometry). We also obtained molecular mass data on dimeric and monomeric apoA-II using electrospray-ionization mass spectrometry (ESI-MS). The data are compared with other mammalian sequences of apoA-II and are discussed in terms of resulting similarities and variations in the primary sequences.
authors.affiliation: Boyer Hall, The Molecular Biology Institute and The Department of Chemistry and Biochemistry, University of California at Los Angeles, Los Angeles, CA 90095, USA. puppione@chem.ucla.edu
authors.forename: Donald L
authors.initials: DL
authors.lastname: Puppione
authors.forename: Wolfgang H
authors.initials: WH
authors.lastname: Fischer
authors.forename: Minkyu
authors.initials: M
authors.lastname: Park
authors.forename: Julian P
authors.initials: JP
authors.lastname: Whitelegge
authors.forename: Verne N
authors.initials: VN
authors.lastname: Schumaker
authors.forename: Shoulamit
authors.initials: S
authors.lastname: Golfeiz
authors.forename: Melinda H
authors.initials: MH
authors.lastname: MacDonald
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016633:Apolipoprotein A-II / Q000378:metabolism*; D019281:Dimerization; D006736:Horses; D006801:Humans; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D021241:Spectrometry, Mass, Electrospray Ionization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D016633:Apolipoprotein A-II