Insights into animal and plant lectins with antimicrobial activities

Abstract

Lectins are multivalent proteins with the ability to recognize and bind diverse carbohydrate structures. The glyco -binding and diverse molecular structures observed in these protein classes make them a large and heterogeneous group with a wide range of biological activities in microorganisms, animals and plants. Lectins from plants and animals are commonly used in direct defense against pathogens and in immune regulation. This review focuses on sources of animal and plant lectins, describing their functional classification and tridimensional structures, relating these properties with biotechnological purposes, including antimicrobial activities. In summary, this work focuses on structural-functional elucidation of diverse lectin groups, shedding some light on host-pathogen interactions; it also examines their emergence as biotechnological tools through gene manipulation and development of new drugs.

Figure 1

Lectin tridimensional structures in (A) arcein from Phaseolus vulgaris L. (pdb: 1ioa) [152]; (B) amaranthin from Amaranthus caudatus (pdb: 1jly) [138]; (C) ricin from Ricinus communis (pdb: 3rti) [140]; (D) jacalin from Artocarpus integer (pdb: 1m26) [142]; (E) galectin-3 from Homo sapiens (pdb: 2xg3) [145]; (F) calreticulin from Mus musculus (pdb: 3o0w) [147]; (G) Homo sapiens L-type (pdb: 4gkx) [150] and (H) Homo sapiens C-type (pdb: 1pwb) [151]. The colors yellow and white represented the secondary structures of β-sheet, α-helices in lectins, respectively. In addition, blue represents the Ca²⁺ ion and carbohydrates are represented in ball and stick.