Guzzetta A W, Clark P, Tappe R, Budzikiewicz H
Department of Analytical Chemistry, Scios Inc., Mountain View, CA, USA.
Z Naturforsch C J Biosci. 1999 Mar-Apr;54(3-4):175-80. doi: 10.1515/znc-1999-3-406.
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.
在大肠杆菌发酵后，一种紫色物质（4）与重组人B型利钠肽（hBNP）部分共纯化。通过核磁共振、电喷雾和快原子轰击质谱法阐明了该化合物的结构。发色团是一个1,4 - 萘醌，通过其NH2 - 和SH - 基团与七肽的N端半胱氨酸缩合形成一个二氢噻嗪环。通过质谱技术确定肽序列为Cys - Lys - Val - Leu - Arg - Arg - His。碰撞诱导解离（CID）和数据库匹配将其鉴定为32个氨基酸的重组肽hBNP的C末端。N端半胱氨酸的这种修饰可能是一种更普遍的现象，对微生物生产异源蛋白质具有重要意义。
