Transacylase‐like structure and its role in substrate channeling of 6‐hydroxymellein synthase, a multifunctional polyketide biosynthetic enzyme in carrot cell extracts

FEBS Letters

Kurosaki, Fumiya¹ 

[1] Cell Biology Laboratory, Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Sugitani, Toyama 930-01, Japan

关键词: Multifunctional enzymel Polyketide biosynthesis;    Transacylase;    Substrate channeling;    Chemical modification of reaction center;    Daucus carota L;   

DOI  :  10.1016/0014-5793(95)01498-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

6-Hydroxymellein synthase, a multifunctional polyketide biosynthetic enzyme of carrot, lost the binding ability toward its co-substrates, acetyl- and malonyl-CoAs, by the treatment with the blocking reagents for serine-OH. In contrast, the enzyme retained the binding ability even when the two SH groups at the reaction center (cysteine-SH of the condensation enzyme and cysteamine-SH of acyl carrier protein) were blocked, and one substrate bound to the SH-blocked enzyme was readily replaced by the other. It appeared that the cysteine-SH accepted only acetyl moiety while cysteamine-SH was preferentially malonylated in the presence of both of the substrates. These results suggest that transacylase-like domain is involved in the structure of 6-hydroxymellein synthase as a common primary binding site of its co-substrates, and acetyl and malonyl moieties are properly channeled from their CoA esters to cysteine-SH and acyl carrier protein-SH via this domain, respectively.

【 授权许可】

Unknown