The derivation of the oxygen atoms of the 131‐oxo and 3‐acetyl groups of bacteriochlorophyll a from water in Rhodobacter sphaeroides cells adapting from respiratory to photosynthetic conditions: evidence for an anaerobic pathway for the formation of isocyclic ring E

FEBS Letters

Schäfer, W.²  Katheder, Ingrid¹  Scheer, H.¹  Porra, R.J.¹ 

[1] Botanisches Institut der Universität München, D-80638 München, Germany;Max-Planck-Institut für Biochemie, D-82152 Martinsried, Germany

关键词: Biosynthesis;    Bacteriochlorophyll a;    Isocyclic ring E;    Anaerobic cyclization;    18O-labelling;    Mass spectrometry;    BChl;    bacteriochlorophyll;    BPhe;    bacteriopheophytin;    Chl;    chlorophyll;    Chlide;    chlorophyllide;    The IUPAC-IUB numbering (see Fig. 1) and nomenclature systems [19] have been used together with [] bracket notation for substituents;   

DOI  :  10.1016/0014-5793(95)00854-3

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Using mass spectrometry, we have demonstrated ¹⁸O-labelling of both the 13¹-oxo and 3-acetyl groups of newly-formed bacteriochlorophyll a synthesized by Rhodobacter sphaeroides cells during adaptation from respiratory to photosynthetic conditions in the presence of H₂ ¹⁸O. This derivation of the 13¹-oxo group of bacteriochlorophyll a from water provides a stark constrast with that of chlorophylls in higher plants where ring E formation is an aerobic process in which the 13¹-oxo group arises from molecular oxygen via an oxygenase activity. The formation of the 3-acetyl group of bacteriochlorophyll a, however, is consistent with the enzymic hydration of the 3-vinyl group of a derivative of chlorophyll a.

【 授权许可】

Unknown