Dual positional substrate specificity of rice allene oxide synthase-1: insight into mechanism of inhibition by type II ligand imidazole

BMB Reports

关键词: Allene oxide synthase;    Cytochrome P450;    Enzyme;    Lipid;    Octadecanoid;   

DOI  :  http://dx.doi.org/10.5483/BMBRep.2013.46.3.117

来源: DOAJ

【 摘 要 】

Phylogenetic and amino acid sequence analysis indicated thatrice allene oxide synthase-1 (OsAOS1) is CYP74, and is clearlydistinct from CYP74B, C and D subfamilies. Regio- andstereo-chemical analysis revealed the dual substrate specificityof OsAOS1 for (cis,trans)-configurational isomers of 13(S)- and9(S)-hydroperoxyoctadecadienoic acid. GC-MS analysis showedthat OsAOS1 converts 13(S)- and 9(S)-hydroperoxyoctadecadi(tri)enoic acid into their corresponding allene oxide.UV-Visible spectral analysis of native OsAOS1 revealed a Soretmaximum at 393 nm, which shifted to 424 nm with severalclean isobestic points upon binding of OsAOS1 to imidazole.The spectral shift induced by imidazole correlated withinhibition of OsAOS1 activity, implying that imidazole maycoordinate to ferric heme iron, triggering a heme-iron transitionfrom high spin state to low spin state. The implications andsignificance of a putative type II ligand-induced spin statetransition in OsAOS1 are discussed. [BMB Reports 2013; 46(3):151-156]

【 授权许可】

Unknown