title: Structure elucidation of a purple peptide found during the purification of a recombinant protein from Escherichia coli.
abstract: A purple substance (4) partially co-purified with a recombinant human B-type natriuretic peptide (hBNP), following an E. coli fermentation. The structure of the compound was elucidated by NMR, electrospray and FAB mass spectrometry. The chromophore is a 1,4-naphthoquinone condensed with the N-terminal cysteine of a heptapeptide by its NH2- and SH-groups to form a dihydro-thiazine ring. The peptide sequence was determined as Cys-Lys-Val-Leu-Arg-Arg-His by mass spectrometric techniques. CID and data base matching identified it as the C-terminus of the 32-amino-acid recombinant peptide hBNP. This modification of an N-terminal Cys may be a more general phenomenon with implications for the production of heterologous proteins by microorganisms.
authors.affiliation: Department of Analytical Chemistry, Scios Inc., Mountain View, CA, USA. guzzetta@sciosinc.com
authors.forename: A W
authors.initials: AW
authors.lastname: Guzzetta
authors.forename: P
authors.initials: P
authors.lastname: Clark
authors.forename: R
authors.initials: R
authors.lastname: Tappe
authors.forename: H
authors.initials: H
authors.lastname: Budzikiewicz
mesh_terms: D000595:Amino Acid Sequence; D009320:Atrial Natriuretic Factor / Q000302:isolation & purification*; D004926:Escherichia coli / Q000737:chemistry / Q000378:metabolism*; D005285:Fermentation; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D020097:Natriuretic Peptide, Brain; D009842:Oligopeptides / Q000737:chemistry* / Q000302:isolation & purification; D011994:Recombinant Proteins / Q000302:isolation & purification; D016339:Spectrometry, Mass, Fast Atom Bombardment
chemical_list: D009842:Oligopeptides; D011994:Recombinant Proteins; D020097:Natriuretic Peptide, Brain; D009320:Atrial Natriuretic Factor