Cloning of ATP-Citrate Lyase (acl1) from Aspergillus niger and its Expression in Escherichia coli

Abstract

Aspergillus niger is an important strain used for industrial fermentation of citrate. The production of citrate is closely related to the growth and metabolism of A. niger. ATP-citrate lyase (ACL) is responsible for catalyzing the conversion of citrate into oxaloacetate and acetyl-CoA, which is a bridge between glucose metabolism and fatty acid synthesis. In A. niger, tandem divergently transcribed genes (acl1 and acl2) encode the subunits of ACL, whose physiological function is unclear. In this study, acl1 was obtained from A. niger by RT-PCR. The sequencing result was consistent with the sequence of genome database. We constructed the expression vector pET28a+-acl1- his6 which was suitable for the efficient expression in Escherichia coli BL21. After purification with Ni2+ chelating chromatography column, SDS-PAGE analysis showed that the molecular mass of the ACL1 was 66 KDa. The result laid the foundation for further research about protease characteristics and physiological functions of ACL1 in A. niger. © Springer-Verlag Berlin Heidelberg 2014.