121st General Meeting of the KCS

Type Poster Presentation
Area Life Chemistry
Room No. Event Hall
Time 4월 20일 (금요일) 11:00~12:30
Code BIO.P-275
Subject Dimeric structure constitutes an important oligomeric states of rice allene oxide cyclase functioning as a Nazarov cyclase
Authors Sereyvath Yoeun, Kyoungwon Cho1, Oksoo Han1,*
Department of Biotechnology, Chonnam National University, Korea
1Department of Molecular Biotechnology, Chonnam National University, Korea
Abstract Allene oxide cyclase catalyzes stereospecific conversion of 12,13(S)-epoxy-9(Z),11,15(Z)-octadecatrienoic acid (12,13-EOT) into cis(+)-12-oxophytodienoic acid in jasmonic acid biosynthesis. Chloroplastidal localization of rice allene oxide cyclase (OsAOC) was confirmed and roles of the N-terminal chloroplast transit peptide in oligomeric states were analyzed in truncated or fused OsAOC with rice allene oxide synthase-1 (OsAOS1). Analysis by native gel and gel filtration indicated that OsAOC formed multimers. Results from cross-linking experiment suggested that OsAOC was in diverse oligomeric states including monomeric, dimeric, multimeric structures in solution. Temperature dependent partial denaturation with SDS indicated that OsAOC is in dimeric state at room temperature. Studies on OsAOS1-OsAOC fusion proteins confirmed that N-terminal pre-sequence of OsAOC is sliced. Dimeric state was also detected in the partially denatured OsAOC-OsAOS1 fusion protein. Coupled reaction of OsAOC with OsAOS1 indicated that the yield reached to a maximal saturation point at 5:1 molar ratio of OsAOC to OsAOS1 in the production of cis(+)-12-oxophytodienoic acid. Our results suggest that dimeric OsAOC possibly interacts with monomeric OsAOS1 to from a trimer for efficient substrate channeling of the allene oxide. Conceptual similarities in mechanism and stereochemical control of allene oxide cyclase as a Nazarov cyclase are discussed.
E-mail sereyvath@gmail.com