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

BMB Reports

Sereyvath Yoeun^1¹  Randeep Rakwal^2² 

[1] Department of Molecular Biotechnology and Kumho Life Science Laboratory, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 500-757, Korea^1;Health Technology Research Center (HTRC), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8569, Japan^2

关键词: Allene oxide synthase;   

DOI  :  

学科分类：生物化学/生物物理

来源: Korean Society for Biochemistry and Molecular Biology

【 摘 要 】

Phylogenetic and amino acid sequence analysis indicated that rice allene oxide synthase-1(OsAOS1) is CYP74, and is clearly distinct from CYP74B, C and D subfamilies. Regio- and stereo-chemical analysis revealed the dual substrate specificity of OsAOS1 for (cis,trans)-configurational isomers of 13(S)- and 9(S)-hydroperoxyoctadecadienoic acid. GC-MS analysis showed that 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 Soret maximum at 393 nm, which shifted to 424 nm with several clean isobestic points upon binding of OsAOS1 to imidazole. The spectral shift induced by imidazole correlated with inhibition of OsAOS1 activity, implying that imidazole may coordinate to ferric heme iron, triggering a heme-iron transition from high spin state to low spin state. The implications and significance of a putative type II ligand-induced spin state transition in OsAOS1 are discussed.

【 授权许可】

Unknown