Small Peptides in the Detection of Mycotoxins and Their Potential Applications in Mycotoxin Removal

Abstract

Mycotoxins pose significant risks to humans and livestock. In addition, contaminated food- and feedstuffs can only be discarded, leading to increased economic losses and potential ecological pollution. Mycotoxin removal and real-time toxin level monitoring are effective approaches to solve this problem. As a hot research hotspot, small peptides derived from phage display peptide libraries, combinatorial peptide libraries, and rational design approaches can act as coating antigens, competitive antigens, and anti-immune complexes in immunoassays for the detection of mycotoxins. Furthermore, as a potential approach to mycotoxin degradation, small peptides can mimic the natural enzyme catalytic site to construct artificial enzymes containing oxidoreductases, hydrolase, and lyase activities. In summary, with the advantages of mature synthesis protocols, diverse structures, and excellent biocompatibility, also sharing their chemical structure with natural proteins, small peptides are widely used for mycotoxin detection and artificial enzyme construction, which have promising applications in mycotoxin degradation. This paper mainly reviews the advances of small peptides in the detection of mycotoxins, the construction of peptide-based artificial enzymes, and their potential applications in mycotoxin control.

Keywords: artificial enzymes; mycotoxin control; mycotoxin detection; mycotoxin removal; small peptides.

Figure 1

Small peptides in mycotoxin detection and potential applications in mycotoxin degradation.

Figure 2

The basic structure and life cycle of the M13 bacteriophage. (A) Structure of the M13 bacteriophage; (B) the life cycle of the M13 bacteriophage; (C) commercial M13 bacteriophage display peptide library. RF: Replicate form; pV: Phage protein.

Figure 3

The one-bead one-compound combinatorial peptide library. A, B, and C represent any of the amino acids.

Figure 4

Rationally designed peptide receptor binding with OTA ((A): GPAGIDGPAGIRC; (B): CSIVEDGL) [13]. Peptide sequences are represented as space-filled, and OTA and AFB₁ as stick and ball structures.

Figure 5

Peptides as competing antigens for mycotoxins detection. (A) FB₁ detection; Reprinted with permission from Ref. [77]. 2017, Anal. Chem. (B) ZEN detection; Reprinted with permission from Ref. [73]. 2020, Biosens. Bioelectron. (C) AFB₁ detection; Reprinted with permission from Ref. [62]. 2019, Talanta. (D) OTA detection; Reprinted with permission from Ref. [60]. 2016, Talanta.

Figure 6

(A) Schematic of mimotope fusion protein as coating antigens for mycotoxin detection; Reprinted with permission from Ref. [11]. 2021, Food Chem. (B,C) Mimotope fusion protein as coating antigens for mycotoxin detection; (a) Biological expression strategy of peptide-MBP fusion protein, (b) Fabrication process of the prepared QDs/QBs-mAb probes, (c) schematic illustration of the tricolor mICA, (d) schematic illustration for the interpretation of test results; Reprinted with permission from Ref. [67], 2014, Food Control, and Ref. [86], 2020, J. Agric. Food. Chem. (D,E) Peptides as coating antigens for mycotoxin detection; Reprinted with permission from [74], 2022, J. Food Saf., and Ref. [75], 2013, J. Agric. Food. Chem.

Figure 7

Peptides as anti-immune complexes for small-molecule contaminant detection (SMC). (A) The process of panning anti-immune complex phages and establishing phage anti-immune complex assay (PHAIA). Reprinted with permission from Ref. [90]. 2007, Anal. Chem. (B) Noncompetitive magnetic-phage anti-immune complex immunoassay (Nc-MCLEIA) for AFB₁ detection. Reprinted with permission from Ref. [61]. 2022, Food Chem. (C) Multivalent display anti-immunocomplex peptides on verotoxin for clomazone detection [92]; (a). The anti-immuncomplex peptide selected from phage libraries, (b). Peptide coding sequence cloned into the pNvtx vector and fused to the VTX gene, (c). Recombinant nanopeptamer conjugated to peroxidase to detect the formation of the immunocomplex.

Figure 8

Artificial enzyme construction process by mimicking nature enzymes.

Figure 9

Peptide-based oxidoreductase mimics with natural heme-containing enzyme activity. (A) Laccase activity. Adapted from Ref. [101]. (B) Peroxidase activity [97]. (C,D) Immobilized into a mesoporous metal-organic framework. Reprinted with permission from Ref. [96], 2020, Catal. Commun., and Ref. [136], 2011, J. Am. Chem. Soc.

Figure 10

Peptide-based hydrolase mimics with esterase activity. (A) immobilized onto gold nanoparticles; (a) Peptide sequences of E3H15 and K3, (b) The structure of Au@E3H15 and mechanism for regulated catalytic activity, (c) Proposed mechanism for the hydrolysis of pNPA catalyzed by E3H15 and Au@E3H15 monolayer. Reprinted with permission from Ref. [108]. 2017, Biomacromolecules. (B) having catalytically active Cys-His-Glu triads by a de novo design; (a) The structure of CC-Hept-Ile-Cys-Ile, (b) Proposed mechanism for the reaction of CC-Hept-Cys-His-Glu with pNPA via a thioester intermediate. Adapted from Ref. [143]. (C) having a small cleft and open zinc coordination site; (a) The structure of MID1-zinc, (b) Proposed mechanism for the reaction of MID1-zinc with pNPA. Reprinted with permission from Ref. [121]. 2012, Biochemistry. (D) capable of self-assembling into amyloid structures; (a) Peptide designs, (b) The structure of peptide III, (c) The proposed mechanism of hydrolysis for the substrate pNPA by fibrils of peptide III. Reprinted with permission from Ref. [118]. 2017, Nanoscale.

Figure 11

Peptide-based lyase mimics inspired by natural human carbonic anhydrase. (A) Peptide-based artificial enzyme capable of self-assembling into nanofibers; (a) Structure of human carbonic anhydrase showing a typical metal-binding motif, (b) Structure and assembly process of artificial enzyme. Adapted from Ref. [131]. (B) Artificial protein containing two separate metal sites by a de novo design; (a) Top-down view of the structural trigonal thiolate site (right) and side view of the tetrahedral catalytic site (left), (b) One of two trimers found in the asymmetric unit of the crystal structure. Adapted from Ref. [107]. (C) single phenylalanine self-assembling into needle-like architectures with carbonic anhydrase activity. Reprinted with permission from Ref. [93]. 2020, ACS Catal.

Figure 12

Removal of OTA by microbial-source small molecular substances; (A) Brevundimonas naejangsanensis ML17 source < 3 kDa ultrafiltration fraction for OTA degradation; Data with different lowercase letters were considered to be significantly different (p < 0.05) by Duncan’s multiple comparison test; Reprinted with permission from Ref. [22]. 2022, Food Control. (B) Bacillus subtilis CW14 source < 3 kDa ultrafiltration fraction for OTA degradation; Bars with *** were significantly different based on ANOVA test (p < 0.001); Reprinted with permission from Ref. [21]. 2018, World Mycotoxin J. (C) Structure of the small peptide in Figure 12D predicted with PEP-FOLD 3.5 and displayed by pyMOL; (D) list of peptides in the Bacillus subtilis CW14 < 3 kDa ultrafiltration fraction, identified by LC-ESI-MS/MS using Mascot serve. Reprinted with permission from Ref. [21]. 2018, World Mycotoxin J.