title: Endogenous peptide discovery of the rat circadian clock: a focused study of the suprachiasmatic nucleus by ultrahigh performance tandem mass spectrometry.
abstract: Understanding how a small brain region, the suprachiasmatic nucleus (SCN), can synchronize the body's circadian rhythms is an ongoing research area. This important time-keeping system requires a complex suite of peptide hormones and transmitters that remain incompletely characterized. Here, capillary liquid chromatography and FTMS have been coupled with tailored software for the analysis of endogenous peptides present in the SCN of the rat brain. After ex vivo processing of brain slices, peptide extraction, identification, and characterization from tandem FTMS data with <5-ppm mass accuracy produced a hyperconfident list of 102 endogenous peptides, including 33 previously unidentified peptides, and 12 peptides that were post-translationally modified with amidation, phosphorylation, pyroglutamylation, or acetylation. This characterization of endogenous peptides from the SCN will aid in understanding the molecular mechanisms that mediate rhythmic behaviors in mammals.
authors: Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
authors: Ji Eun
authors: JE
authors: Lee
authors: Norman
authors: N
authors: Atkins
authors: Nathan G
authors: NG
authors: Hatcher
authors: Leonid
authors: L
authors: Zamdborg
authors: Martha U
authors: MU
authors: Gillette
authors: Jonathan V
authors: JV
authors: Sweedler
authors: Neil L
authors: NL
authors: Kelleher
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000378:metabolism; D009479:Neuropeptides / Q000737:chemistry / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D010455:Peptides / Q000737:chemistry / Q000378:metabolism*; D051381:Rats; D020318:Rats, Long-Evans; D013493:Suprachiasmatic Nucleus / Q000378:metabolism*; D053719:Tandem Mass Spectrometry / Q000379:methods* / Q000592:standards*
chemical_list: D050505:Mutant Proteins; D009419:Nerve Tissue Proteins; D009479:Neuropeptides; D010446:Peptide Fragments; D010455:Peptides; C492467:manserin, rat; C046788:cerebellin