Interaction of L-amino Acids with the Fusion Structures of a Cysteine Proteinase/Cystatin Pair

In a basic investigation, the molecular interactions between 2 different fused products of Arabidopsis cysteine proteinase (CP) and cysteine proteinase inhibitor (CPI) pair "namely R1: H2N-maltose-binding protein-CPI-CP-COOH and R2: H2N-maltose binding protein-CP-CPI-COOH" and 4 different L-amino acids including L-Ala, L-Ser, L-Asp, and L-Phe were analyzed using experimental methods and computational tools. The activity of CP relatively increased in purified R2 product in which test L-amino acids tend to interact with CP/CPI pair. On the other hand, the functionality of R1 product (having no tendency to interact with CP/CPI pair) was not influenced by L-amino acids. Detection of the effect of L-enantiomers of amino acids on the fusion forms of 2 functionally related proteins such as CP and CPI is the first ever time work on this research area. As a research recommendation, manufacturing the switchable biological systems expressing the fused forms of CP/CPI pair was proposed to control the relative activities of proteolytic compounds in different environments in the future.