Identification of the conserved domains of ADP-Glucose Pyrophosphorylase (AGPase) protein in sweetpotato (Ipomoea batatas (L.) Lam.) and its two wild relatives

Abstract

The conserved domains are defined as recurring units in molecular evolution, which are commonly used to interpret the molecular function and biochemical structure of proteins. The AGPase amino acid sequences of three species from the Ipomoea genus were identified to investigate their physicochemical and biochemical characteristics. The molecular weights (MW), isoelectric point (pI), instability index (II), and grand average of hydropathy (GRAVY) showed considerable differences in each plant. The aliphatic index (AI) values of sweetpotato AGPase proteins were higher in the small subunit than in the large subunit. The AGPase proteins from sweetpotato contain an LbH_G1P_AT_C domain in the C-terminal region and various domains (NTP_transferase, ADP_Glucose_PP, or Glyco_tranf_GTA) in the N-terminal region. On the other hand, most of its two relatives (I. trifida and I. triloba) only contain the NTP_transferase domain in the N-terminal region. These findings suggested that these conserved domains were species specificity and related to the subunit types of AGPase proteins. The study may enable research on the AGPase-related specific characteristics of sweetpotatoes, which do not exist in the other two species, such as starch metabolism and tuberization mechanism.