In Silico Structural Characteristics and α-Amylase Inhibitory Properties of Ric c 1 and Ric c 3, Allergenic 2S Albumins from Ricinus communis Seeds

• Published in: Journal of agricultural and food chemistry 2011-05, Vol.59 (9), p.4814-4821
• Main Authors: Nascimento, Viviane Veiga Do, Castro, Helena Carla, Abreu, Paula Alvarez, Oliveira, Antônia Elenir Amâncio, Fernandez, Jorge Hernandez, Araújo, Jucélia Da Silva, Machado, Olga Lima Tavares
• Format: Article
• Language: English
• Subjects: 2S Albumins, Plant - chemistry; 2S Albumins, Plant - metabolism; 2S Albumins, Plant - pharmacology; albumins; allergenicity; allergens; alpha-amylase; alpha-Amylases - antagonists & inhibitors; alpha-Amylases - chemistry; alpha-Amylases - metabolism; Amino Acid Sequence; Animals; Antigens, Plant - chemistry; Antigens, Plant - metabolism; Antigens, Plant - pharmacology; artificial diets; bioassays; Biological and medical sciences; Callosobruchus maculatus; Coleoptera - chemistry; Coleoptera - enzymology; Crop and Animal Protection Chemistry; diabetes; Enzyme Inhibitors - chemistry; Enzyme Inhibitors - metabolism; Enzyme Inhibitors - pharmacology; Food industries; Fundamental and applied biological sciences. Psychology; General aspects; Insect Proteins - antagonists & inhibitors; Insect Proteins - chemistry; Insect Proteins - metabolism; insects; Kinetics; larvae; larval development; mammals; Methods of analysis, processing and quality control, regulation, standards; Molecular Sequence Data; nuclear magnetic resonance spectroscopy; plant protection; Ricinus communis; Ricinus communis - chemistry; Ricinus communis - metabolism; seeds; Seeds - chemistry; Seeds - metabolism; Sequence Alignment; Tenebrio molitor; Zabrotes subfasciatus
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf104638b

The major Ricinus communis allergens are the 2S albumins, Ric c 1 and Ric c 3. These proteins contain a trypsin/α-amylase inhibitor family domain, suggesting that they have a role in insect resistance. In this study, we verified that Ric c 1 and Ric c 3 inhibited the α-amylase activity of Callosobruchus maculatus, Zabrotes subfasciatus, and Tenebrio molitor (TMA) larvae as well as mammalian α-amylase. The toxicity of 2S albumin was determined through its incorporation in C. maculatus larvae as part of an artificial diet. Bioassays revealed that 2S albumin reduced larval growth by 20%. We also analyzed the tridimensional structures of Ric c 1 and Ric c 3 by (a) constructing a comparative model of Ric c 1 based on Ric c 3 NMR structure and (b) constructing the theoretical structure of the Ric c 1−TMA and Ric c 3−TMA complexes. Our biological and theoretical results revealed that Ric c 1 and Ric c 3 are a new class of α-amylase inhibitors. They could potentially be used to help design inhibitors that would be useful in diverse fields, ranging from diabetes treatment to crop protection.