The Crystallographic Research Of N-acyltransferases In Rice

Rice is known as a model organism of monocots and a staple crop,of which the basic research on metabolic network has great application prospects.Acylation plays an important role in modifying the secondary metabolites and acts an indispensable part in the metabolic network of plants.The BAHD superfamily involved in the acylation of plant secondary metabolites such as flavonoids,alkaloids,terpenoids and volatile esters is a group of special acyltransferases which specially exist in plants and a few funguses.The N-acyltransferases are a group of acyltransferases belonging to the BAHD superfamily,which are responsible for catalyzing transfer of acyl groups from a donor molecule to the amino group of an acceptor molecule to yield amide.In most cases,the biochemical function of N-acyltransferases has been characterized.However,the structure of N-acyltransferases and the structural basic determining their substrate-specificity is still obscure.In this study,we expressed,purified and crystallized several BAHD family members proteins from rice genome.We successfully determined structures of N-acyltransferases OsAT9.2 and OsAT10.1,their resolution is 1.8 (?) and 2.3 (?) respectively.Based on the structure superimposing,multiple sequence alignment and molecular simulation,the structure revealed the possible roles of His155,Asp159,Arg280,Arg286,Asn300,Glu369,Asp371 and Ser372 of OsAT10.1 and Tyr37 of OsAT9.2 in catalysis and specificity.Combining analysis of enzyme activity data of the wild type and mutants,we proposed a role for Arg280,Asp371 and Ser372 in substrate recognition and catalytic mechanism of OsAT10.1.